GSS Logo
Page Heading
• Global Systems Science

A CHANGING COSMOS

Home Button
About Button
Student Books
Staying Uptodate Button
Teacher Guides
Software
Order Button

1. Cosmic Cataclysms

2011 Feb 2. NASA RELEASE 11-029: NASA's Neowise Completes Scan For Asteroids And Comets. Excerpt: WASHINGTON -- NASA's NEOWISE mission has completed its survey of small bodies, asteroids and comets, in our solar system. The mission's discoveries of previously unknown objects include 20 comets, more than 33,000 asteroids in the main belt between Mars and Jupiter, and 134 near-Earth objects (NEOs)...asteroids and comets with orbits that come within 28 million miles of Earth's path around the sun. NEOWISE is an enhancement of the Wide-field Infrared Survey Explorer, or WISE, mission that launched in December 2009. WISE scanned the entire celestial sky in infrared light about 1.5 times. It captured more than 2.7 million images of objects in space, ranging from faraway galaxies to asteroids and comets close to Earth. In early October 2010, after completing its prime science mission, the spacecraft ran out of frozen coolant that keeps its instrumentation cold. However, two of its four infrared cameras remained operational. These two channels were still useful for asteroid hunting, so NASA extended the NEOWISE portion of the WISE mission by four months, with the primary purpose of hunting for more asteroids and comets, and to finish one complete scan of the main asteroid belt.
 ...In addition to discovering new asteroids and comets, NEOWISE also confirmed the presence of objects in the main belt that already had been detected. In just one year, it observed about 153,000 rocky bodies out of approximately 500,000 known objects. Those include the 33,000 that NEOWISE discovered. ...The first batch of observations from the WISE mission will be available to the public and astronomical community in April…. For more information about WISE, visit: http://www.nasa.gov/wise [Mission website - http://wise.ssl.berkeley.edu/]

2010 September. Stars on Radio. By Kathleen M. Wong, Science Matters @ Berkeley. Excerpt: The radio sky to modern astronomers is much like the West was to Lewis and Clark. “It’s all very sparsely explored at this point,” says Geoffrey Bower. A Berkeley professor of astronomy, Bower is conducting systematic radio wavelength surveys of the heavens. Such comprehensive viewing goals, made possible by modern increases in data storage and processing abilities, were identified this August as among the highest priorities in astronomy by the National Academy of Sciences.
During his surveys, Bower expects to uncover not only new phenomena, but invent better ways to decipher the physics and structure of the universe.
...Bower has found one such tool by analyzing neutron stars. These ultra-dense collapsed stars can emit brief but astoundingly powerful bursts of radio wavelength energy…. Bower hopes to use these fleeting flashes to illuminate the spaces between galaxies.
...Bower’s radio surveys have already turned up another promising space exploration technique: astrometric planet hunting. …Radio measurements, they realized, yield measurements of a star’s position so precise that they could reveal the back-and-forth wobble caused by the orbit of a large planet. Bower is now using this method to search for extrasolar planets.

2010 August 23. Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies. By Committee to Review Near-Earth Object Surveys and Hazard Mitigation Strategies; National Research Council. Excerpt: The United States spends approximately $4 million each year searching for near-Earth objects (NEOs). The objective is to detect those that may collide with Earth. The majority of this funding supports the operation of several observatories that scan the sky searching for NEOs. This, however, is insufficient in detecting the majority of NEOs that may present a tangible threat to humanity....
...Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies identifies the need for detection of objects as small as 30 to 50 meters as these can be highly destructive...
...Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies is a useful guide for scientists, astronomers, policy makers and engineers.

2010 August 20. New Worlds, New Horizons in Astronomy and Astrophysics. By Committee for a Decadal Survey of Astronomy and Astrophysics; National Research Council Excerpt: The field of astronomy and astrophysics is making new connections to physics, chemistry, biology, and computer science....
...New Worlds, New Horizons in Astronomy and Astrophysics outlines a plan for ground- and space- based astronomy and astrophysics for the decade of the 2010's...
...The book recommends beginning construction on survey telescopes in space and on the ground to investigate the nature of dark energy, as well as the next generation of large ground-based giant optical telescopes and a new class of space-based gravitational observatory to observe the merging of distant black holes and precisely test theories of gravity. New Worlds, New Horizons in Astronomy and Astrophysics recommends a balanced and executable program that will support research surrounding the most profound questions about the cosmos...
...The discoveries ahead will facilitate the search for habitable planets, shed light on dark energy and dark matter, and aid our understanding of the history of the universe and how the earliest stars and galaxies formed.

2010 March 9. Alvarez Theory on Dinosaur Die-Out Upheld: Experts Find Asteroid Guilty of Killing the Dinosaurs. By Lynn Yarris, Lawrence Berkeley National Laboratory. Excerpt: In the March 5, 2010 edition of the journal Science, an international panel of 41 experts in geology, paleontology and other related fields, after an exhaustive review of the data, declared an end to a 30 year controversy over what triggered the extinction of the dinosaurs – an asteroid or volcanoes. The panel ruled in favor of the asteroid, a theory first put forth in 1980 by one of Berkeley Lab’s greatest scientists, the late Nobel laureate Luis Alvarez, and his son Walter, a geologist with UC Berkeley....

2009 October 26. Asteroid blast reveals holes in Earth's defences. By David Shiga, NewScientist. Excerpt: As the US government ponders a strategy to deal with threatening asteroids, a dramatic explosion over Indonesia has underscored how blind we still are to hurtling space rocks.
On 8 October an asteroid detonated high in the atmosphere above South Sulawesi, Indonesia, releasing about as much energy as 50,000 tons of TNT, according to a NASA estimate released on Friday. That's about three times more powerful than the atomic bomb that levelled Hiroshima, making it one of the largest asteroid explosions ever observed.
However, the blast caused no damage on the ground because of the high altitude, 15 to 20 kilometres above Earth's surface, says astronomer Peter Brown of the University of Western Ontario (UWO), Canada.
...The amount of energy released suggests the object was about 10 metres across, the researchers say. Such objects are thought to hit Earth about once per decade.
No telescope spotted the asteroid ahead of its impact. That is not surprising, given that only a tiny fraction of asteroids smaller than 100 metres across have been catalogued, says Tim Spahr, director of the Minor Planet Center in Cambridge, Massachusetts. Yet objects as small as 20 or 30 metres across may be capable of doing damage on the ground, he says....

2009 Oct 7. NASA RELEASE: 09-232, NASA REFINES ASTEROID APOPHIS' PATH TOWARD EARTH. Excerpt: PASADENA, Calif. -- Using updated information, NASA scientists have recalculated the path of a large asteroid. The refined path indicates a significantly reduced likelihood of a hazardous encounter with Earth in 2036.
The Apophis asteroid is approximately the size of two-and-a-half football fields. The new data were documented by near-Earth object scientists Steve Chesley and Paul Chodas at NASA's Jet Propulsion Laboratory in Pasadena, Calif.
"Apophis has been one of those celestial bodies that has captured the public's interest since it was discovered in 2004," said Chesley. "Updated computational techniques and newly available data indicate the probability of an Earth encounter on April 13, 2036, for Apophis has dropped from one-in-45,000 to about four-in-a million."
...Initially, Apophis was thought to have a 2.7 percent chance of impacting Earth in 2029. Additional observations of the asteriod ruled out any possibility of an impact in 2029. However, the asteroid is expected to make a record-setting -- but harmless -- close approach to Earth on Friday, April 13, 2029, when it comes no closer than 18,300 miles above Earth's surface.
...NASA detects and tracks asteroids and comets passing close to Earth using both ground and space-based telescopes. The Near Earth-Object Observations Program, commonly called "Spaceguard," discovers these objects, characterizes a subset of them and plots their orbits to determine if any could be potentially hazardous to our planet. For more information about asteroids and near-Earth objects, visit: http://www.jpl.nasa.gov/asteroidwatch

2009 October 2. After Asteroid Strike, a Fast Rebound for Some. By Henry Fountain, The NY Times. Excerpt: The asteroid that struck the planet 65 million years ago was very bad for the dinosaurs, as everyone knows, but it wasn’t too good for smaller things, either. Even algae and other primary producers in the ocean were affected, probably because atmospheric debris from the impact reduced the sunlight available for photosynthesis.
But there is new evidence, reported in Science, that primary productivity in the oceans was not down for long. An analysis of sediments along a bluff in Denmark suggests that algae recovered in less than a century.
Julio Sepúlveda, a geochemist at the Massachusetts Institute of Technology and formerly at the University of Bremen in Germany, and colleagues studied a 15-inch layer of clay at Kulstirenden on the island of Zealand.
...Dr. Sepúlveda said the findings showed that “the most dramatic disruption in primary production was for a rather short period of time.” But the overall recovery of the oceans, particularly deep environments, took much longer....

2009 September 23. Space Scientists Weigh Technology, Diplomacy Challenges of Global Asteroid Threat. By Edward W. Lempinen, AAAS News. Excerpt: SAN FRANCISCO—Imagine this scenario: Astronomers discover a previously unknown asteroid. Though it is millions of miles away, initial calculations suggest that it will, in about 15 years, pass dangerously close to Earth. And though its size is modest—about 100 meters at its widest—it is more than big enough to destroy a major city.
If this were a conventional Hollywood thriller, the plot might focus on how nuclear weapons would be deployed and launched to destroy the menacing asteroid. But for former U.S. astronauts Rusty Schweickart and Edward Lu, any such mission to save the Earth would be far more complex. To create the greatest chance of success, they say, it should begin with ambitious science diplomacy and technology research and development long before the asteroid is discovered.
In a symposium at the annual meeting of the AAAS Pacific Division, Schweickart and Lu suggested that novel technology is available that would allow humans to closely track such an asteroid and to redirect its orbit. What's lacking, they said, is political recognition that asteroids will periodically threaten Earth in the future—and that the time to plan and prepare is now.
...They have proposed ambitious efforts to track and respond to threatening "Near-Earth Objects," or NEOs. The centerpiece of their strategy: A relatively simple, unmanned spacecraft that would fly to a suspect NEO and position itself close enough to exert a small pull of gravity; over a period of time, it would "tow" the object into a non-threatening orbit. NASA's Jet Propulsion Laboratory last fall concluded that the plan is viable....

2009 August 15. Report: NASA can't keep up with killer asteroids. By SETH BORENSTEIN, AP Science Writer. Excerpt: NASA is charged with spotting most of the asteroids that pose a threat to Earth but doesn't have the money to complete the job, a federal report says.
That's because even though Congress assigned the space agency that mission four years ago, it never gave NASA the money to build the necessary telescopes, according to the report released Wednesday by the National Academy of Sciences.
Specifically, the mission calls for NASA, by the year 2020, to locate 90 percent of the potentially deadly rocks hurtling through space. The agency says it's been able to complete about one-third of its assignment with the current telescope system.
NASA estimates that there are about 20,000 asteroids and comets in our solar system that are potential threats. They are larger than 460 feet in diameter — slightly smaller than the Superdome in New Orleans. So far, scientists know where about 6,000 of these objects are.
Rocks between 460 feet and 3,280 feet in diameter can devastate an entire region, said Lindley Johnson, NASA's manager of the near-Earth objects program. Objects bigger than that are even more threatening, of course.
Just last month astronomers were surprised when an object of unknown size and origin bashed into Jupiter and created an Earth-sized bruise that is still spreading. Jupiter does get slammed more often than Earth because of its immense gravity, enormous size and location.
...At the moment, NASA has identified about five near-Earth objects that pose better than a 1-in-a-million risk of hitting Earth and being big enough to cause serious damage, Johnson said....

2009 June 11. Planets will collide in 5 billion years. David Perlman, SF Chronicle Science Editor. Excerpt: From chaos we all began, and to chaos we'll all return, but not for a very, very long time - 5 billion years or so, more or less. In the journal Nature today, two French scientists, using arcane mathematical models, predict that in the distant future, the Earth and planet after planet will collide with each other as an inevitable part of the solar system's long-term evolution. For many millennia, the scientists say, the orbits of the solar system's eight planets will remain stable, just as they are today, but eventually small eccentricities in their flight paths around the sun could cause Mercury, Mars, Venus and Earth to smash into each other, either one at a time or all at once - the ultimate chaotic disaster. ... the prophets of eventual doom - astronomer Jacques Laskar and computer engineer Mickael Gastineau of France's Paris Observatory - calculate that the odds are 99-to-1 that the orbits of the four inner planets - Mercury, Venus, Earth and Mars - will remain stable for the full 5 billion years.
The time frame coincides with accepted theory that by the end of that same 5 billion years the sun will have burned up its hydrogen and in a cooler state will inflate itself into what's called a red giant star, engulfing the entire inner solar system while the planets are still colliding. So, either way, the planets of the inner solar system are safe for another 5 billion years, according to Laughlin....

2009 April 28. New Blow Against Dinosaur-killing Asteroid Theory, Geologists Find. NSF Press Release. The enduringly popular theory that the Chicxulub crater holds the clue to the demise of the dinosaurs, along with some 65 percent of all species 65 million years ago, is challenged in a paper to be published in the Journal of the Geological Society on April 27, 2009.

Neil DeGrasse Tyson: Death by Black Hole. Video of astrophysicist Neil DeGrasse Tyson discussing asteroid collision.

2009 January 1. Diamonds Linked to Quick Cooling Eons Ago. By Kenneth Chang, The New York Times. Excerpt: At least once in Earth’s history, global warming ended quickly, and scientists have long wondered why.
Now researchers are reporting that the abrupt cooling — which took place about 12,900 years ago, just as the planet was emerging from an ice age — may have been caused by one or more meteors that slammed into North America.
That could explain the extinction of mammoths, saber-tooth tigers and maybe even the first human inhabitants of the Americas, the scientists report in Friday’s issue of the journal Science.
The hypothesis has been regarded skeptically, but its advocates now report perhaps more convincing residue of impact: a thin layer of microscopic diamonds found in rocks across America and in Europe.
...At each site the scientists looked at, the diamond layer in the rocks correlates to the date of the hypothesized impact. Within the layer, the scientists report finding a multitude of diamond particles, all encased within carbon spheres. “We’ve yet to find a single diamond above it,” Dr. West said. “We’ve yet to find a single diamond below it.”
Perhaps more telling, the scientists reported last month at a meeting of the American Geophysical Union in San Francisco, the carbon atoms inside some of the diamonds are lined up in a hexagonal crystal pattern instead of the usual cubic structure. The hexagonal diamonds, formed by extraordinary heat and pressure, have been found only at impact craters and within meteorites and cannot be formed in forest fires or volcanic eruptions, Dr. West said....

2008 December. Meteorites from the Lone Rock, SK Strewn Field. Web page set up by Bruce McCurdy of the Edmonton Space & Science Foundation showing pictures of the recovery efforts of the meteor impact of 2008 November 20 at 5:26.43 MST.

2008 November 3. Astronomers hunt for Earth-bound killer rocks. By Charles Burress, San Francisco Chronicle. Excerpt: ...Giant rocks from space are hurtling toward us, on track to clobber our planet. But don't panic. Scientists say the next killer asteroid - unlike those that pummeled us in the past - can be deflected if we know about it far enough in advance.
So while many of us sleep, two Bay Area astronomers have recently begun standing sentinel against the cosmic cannonballs that could smash into Earth. Their big eye is "Nellie," the 36-inch reflecting telescope at the Chabot Space & Science Center in the Oakland hills.
"We've not discovered anything," said asteroid-tracker Gerald McKeegan, a member of the Eastbay Astronomical Society, which is affiliated with Chabot. "A lot of what we do is follow-up work."
..."You've got a rock, and now we have to figure out where that rock is going," said Chabot staff astronomer Conrad Jung. "We play a small but important role in trying to figure it out."
The Chabot center recently became the only Bay Area facility on active duty in the Earth-threatening asteroid search when it was selected to join an official worldwide network of observatories tracking potentially catastrophic "NEOs," - space talk for near Earth objects.
...Chances are small that Earth will be hit by an asteroid soon, but the consequences would be so enormous that the U.S. government and many experts around the world say we must begin to prepare. NASA's goal is to locate 90 percent of asteroids that could cause global disasters - those that come close to Earth's orbit and are larger than 1 kilometer in diameter - by the end of this year....

2008 Apr 15. Gauging a Collider's Odds of Creating a Black Hole. By DENNIS OVERBYE, NY Times. Excerpt: ... the Large Hadron Collider... starts smashing protons together this summer at the European Center for Nuclear Research, or Cern, outside Geneva, in hopes of grabbing a piece of the primordial fire, forces and particles that may have existed a trillionth of a second after the Big Bang.
Critics have contended that the machine could produce a black hole that could eat the Earth or something equally catastrophic.
To most physicists, this fear is more science fiction than science fact. ...In a paper published in 2000 with the title "Might a Laboratory Experiment Destroy Planet Earth?" Francesco Calogero, a nuclear physicist at the University of Rome and co-winner of the 1995 Nobel Peace Prize for his work with the Pugwash conferences on arms control, deplored a tendency among his colleagues to promulgate a "leave it to the experts" attitude. ...society has never agreed on a standard of what is safe in these surreal realms when the odds of disaster might be tiny but the stakes are cosmically high. In such situations, probability estimates are often no more than "informed betting odds," said Martin Rees, a Cambridge University cosmologist, the astronomer royal and the author of "Our Final Hour." ...the random nature of quantum physics means that there is always a minuscule, but nonzero, chance of anything occurring, including that the new collider could spit out man-eating dragons.
...Next year will see the release of the film version of "Angels and Demons," ...in which the bad guys use a Cern accelerator to gather antimatter for a bomb to blow up the Vatican, and it includes scenes at Cern.
...Neither Dr. Calogero nor Dr. Rees say they are losing sleep over the collider. Some risk is acceptable, even inevitable, in the pursuit of knowledge, they say, and they trust the physicists who have built it....

2007 September 20. Meteorite likely caused crater in Peru. By MONTE HAYES Associated Press Writer. The Associated Press Excerpt: Peruvian astronomers said Thursday that evidence shows a meteorite crashed near Lake Titicaca over the weekend, leaving an elliptical crater and magnetic rock fragments in an impact powerful enough to register on seismic charts….
The Earth is constantly bombarded with objects from outer space, but most burn up in the atmosphere and never reach the planet's surface. Only one in a thousand rocks that that people claim are meteorites turn out to be real, according to Jay Melosh, an expert on impact craters and professor of planetary science at the University of Arizona….
Such impacts are rare, and astronomists still want to do other tests to confirm the strike…. Meteorites are actually cold when they hit Earth, astronomists say, since their outer layers burn up and fall away before impact…..
More details emerged when astrophysicist Jose Ishitsuka of Peru's Geophysics Institute reached the site about 6 miles from Lake Titicaca. He confirmed that a meteorite caused a crater 42 feet wide and 15 feet deep, the institute's president, Ronald Woodman, told The Associated Press on Thursday.
Ishitsuka recovered a 3-inch magnetic fragment and said it contained iron, a mineral found in all rocks from space. The impact also registered a magnitude-1.5 tremor on the institute's seismic equipment - that's as much as an explosion of 4.9 tons of dynamite, Woodman said….
Peasants living near the crater said they had smelled a sulfurous odor for at least an hour after the meteorite struck and that it had provoked upset stomachs and headaches….
Meteor expert Ursula Marvin said that if people were sickened, "it wouldn't be the meteorite itself, but the dust it raises...."

2007 March 16. The Sky Is Falling. Really. By RUSSELL L. SCHWEICKART (a former Apollo astronaut, is the chairman of the B612 Foundation, which promotes efforts to alter the orbits of asteroids). Tiburon, Calif. Americans who read the papers or watch Jay Leno have been aware for some time now that there is a slim but real possibility - about 1 in 45,000 - that an 850-foot-long asteroid called Apophis could strike Earth with catastrophic consequences on April 13, 2036. What few probably realize is that there are thousands of other space objects that could hit us in the next century that could cause severe damage, if not total destruction.

2007 January 6. What Landed in New Jersey? It Came From Outer Space. By KAREEM FAHIM. Excerpt: The object that tore through the roof of a house in the New Jersey suburbs this week was an iron meteorite, perhaps billions of years old and maybe ripped from the belly of an asteroid, experts who examined it said yesterday. ...it landed - and ruined a second-floor bathroom - the meteorite is only the second found in New Jersey, said Jeremy S. Delaney, a Rutgers University expert who examined it. ...from looking at it, Dr. Delaney and other experts were able to tell that the object it had been part of - perhaps an asteroid - cooled relatively fast. It is magnetic, and reasonably dense, they determined. The leading edge - the one that faced forward as it traveled through the earth's atmosphere - was much smoother, while the so-called trailing edge seemed to have caught pieces of molten metal. ..."The worth of a meteorite like this is almost completely determined by where it fell," said Eric Twelker, a geologist and a dealer in meteorites, who buys and sells perhaps a hundred of them a month on http://meteoritemarket.com, his Web site. He was speaking of the premium placed on meteorites with a compelling back story, like the football-size rock that crashed into a parked Chevrolet in Peekskill, N.Y., in 1992.

2006 November 14 Ancient Crash, Epic Wave. By SANDRA BLAKESLEE, NY Times. Excerpt: Did catastrophe fall from above in 2807 B.C.? Mega-tsunamis following meteor impacts left their mark, researchers say. At the southern end of Madagascar lie four enormous wedge-shaped sediment deposits, called chevrons, that are composed of material from the ocean floor. Each covers twice the area of Manhattan with sediment as deep as the Chrysler Building is high. On close inspection, the chevron deposits contain deep ocean microfossils that are fused with a medley of metals typically formed by cosmic impacts. And all of them point in the same direction - toward the middle of the Indian Ocean where a newly discovered crater, 18 miles in diameter, lies 12,500 feet below the surface. The explanation is obvious to some scientists. A large asteroid or comet, the kind that could kill a quarter of the world's population, smashed into the Indian Ocean 4,800 years ago, producing a tsunami at least 600 feet high, about 13 times as big as the one that inundated Indonesia nearly two years ago. The wave carried the huge deposits of sediment to land. Most astronomers doubt that any large comets or asteroids have crashed into the Earth in the last 10,000 years. But the self-described "band of misfits" that make up the two-year-old Holocene Impact Working Group say that astronomers simply have not known how or where to look for evidence of such impacts along the world's shorelines and in the deep ocean. ...Peter Bobrowski, a senior research scientist in natural hazards at the Geological Survey of Canada, said "chevrons are fantastic features" but do not prove that megatsunamis are real. There are other interpretations for how chevrons are formed, including erosion and glaciation... It is up to the working group to prove its claims, he said. ...Bruce Masse, an environmental archaeologist at the Los Alamos National Laboratory in New Mexico ...thinks he can say precisely when the comet fell: on the morning of May 10, 2807 B.C. Dr. Masse analyzed 175 flood myths from around the world, and tried to relate them to known and accurately dated natural events like solar eclipses and volcanic eruptions. ...14 flood myths specifically mention a full solar eclipse, which could have been the one that occurred in May 2807 B.C. Half the myths talk of a torrential downpour, Dr. Masse said. A third talk of a tsunami. Worldwide they describe hurricane force winds and darkness during the storm. All of these could come from a mega-tsunami. Of course, extraordinary claims require extraordinary proof, Dr. Masse said, "and we're not there yet."

Weather Photography has images of many types of weather/atmospheric phenomena.

 

Archive of Past Articles for Chapter 1

 

 

Chapters

  1. Cosmic Cataclysms
  2. Astronomers' Tools
  3. Cosmic Engines
  4. Fathoming Huge Distances
  5. Color, Temperature, and Age
  6. Dramatic Change in Stars
  7. Planet-Star Systems
  8. Search for Habitable Planets
  9. Cosmos Begins...and Ends?

Archive of Past Articles for All Chapters

General Astronomy Resources

 

2. Astronomers Tools

2009 October 28. Gallery: Images of space transformed by chips. NewScientist. Excerpt: This year's Nobel prize for physics was partly awarded to Willard Boyle and George Smith for inventing the charge-coupled device (CCD), the sensor that acts as the retina of digital cameras. But long before it reached consumers, the technology was used in astronomy. Explore these images to see how CCDs showed us space as never before....

2009 October 7. NASA Telescope Discovers Giant Ring Around Saturn. NY Times. Excerpt: PASADENA, Calif. (AP) -- The Spitzer Space Telescope has discovered the biggest but never-before-seen ring around the planet Saturn, NASA's Jet Propulsion Laboratory announced late Tuesday.
The thin array of ice and dust particles lies at the far reaches of the Saturnian system and its orbit is tilted 27 degrees from the planet's main ring plane, the laboratory said.
JPL spokeswoman Whitney Clavin said the ring is very diffuse and doesn't reflect much visible light but the infrared Spitzer telescope was able to detect it.
Although the ring dust is very cold -- minus 316 degrees Fahrenheit -- it shines with thermal radiation.
No one had looked at its location with an infrared instrument until now, Clavin said....

 

 

Chapters

  1. Cosmic Cataclysms
  2. Astronomers' Tools
  3. Cosmic Engines
  4. Fathoming Huge Distances
  5. Color, Temperature, and Age
  6. Dramatic Change in Stars
  7. Planet-Star Systems
  8. Search for Habitable Planets
  9. Cosmos Begins...and Ends?

Archive of Past Articles for All Chapters

 

3. Cosmic Engines

2009 Feb 11. Solar Dynamics Observatory successfully launched Feb 11. Mission Science Objectives--The scientific goals of the SDO Project are to improve our understanding of seven science questions:
1. What mechanisms drive the quasi-periodic 11-year cycle of solar activity?
2. How is active region magnetic flux synthesized, concentrated, and dispersed across the solar surface?
3. How does magnetic reconnection on small scales reorganize the large-scale field topology and current systems and how significant is it in heating the corona and accelerating the solar wind?
4. Where do the observed variations in the Sun's EUV spectral irradiance arise, and how do they relate to the magnetic activity cycles?
5. What magnetic field configurations lead to the CMEs, filament eruptions, and flares that produce energetic particles and radiation?
6. Can the structure and dynamics of the solar wind near Earth be determined from the magnetic field configuration and atmospheric structure near the solar surface?
7. When will activity occur, and is it possible to make accurate and reliable forecasts of space weather and climate?

2007 April 24. NASA Releases 3D Images of Sun. By THE ASSOCIATED PRESS. Excerpt: GREENBELT, Md. (AP) -- NASA released the first three-dimensional images of the sun Monday, saying the photos taken from twin spacecraft may lead to better predictions of solar eruptions that can affect communications and power lines on Earth. ... 'Wow!''' scientist Simon Plunkett said as he explained the images to a room full of journalists and scientists wearing 3D glasses. The images from the STEREO spacecraft (for Solar Terrestrial Relations Observatory) are available on the Internet and at museums and science centers nationwide. The twin spacecraft, launched in October, are orbiting the Sun, one slightly ahead of the Earth and one behind. The separation, just like the distance between our two eyes, provides the depth perception that allows the 3D images to be obtained. That depth perception is also particularly helpful for studying a type of solar eruption called a coronal mass ejection. Along with overloading power lines and disrupting satellite communications, the eruptions can endanger astronauts on spacewalks. Scientists would like to improve predictions of the arrival time from the current day or so to a few hours, said Russell Howard, principal investigator for the Naval Research Laboratory project. See http://www.nasa.gov/stereo

Archive of Past Articles for Chapter 3

 

 

Chapters

  1. Cosmic Cataclysms
  2. Astronomers' Tools
  3. Cosmic Engines
  4. Fathoming Huge Distances
  5. Color, Temperature, and Age
  6. Dramatic Change in Stars
  7. Planet-Star Systems
  8. Search for Habitable Planets
  9. Cosmos Begins...and Ends?

Archive of Past Articles for All Chapters

 

4. Fathoming Huge Distances

Rich Lohman's Asteroid Parallax Activities:

2011 Jan 12. Cosmology Standard Candle Not So Standard After All. NASA Spitzer Project. Excerpt: PASADENA, Calif. -- Astronomers have turned up the first direct proof that "standard candles" used to illuminate the size of the universe, termed Cepheids, shrink in mass, making them not quite as standard as once thought. The findings, made with NASA's Spitzer Space Telescope, will help astronomers make even more precise measurements of the size, age and expansion rate of our universe.

2009 October 22. Galaxy cluster smashes distance record. EurekAlert. Excerpt: The most distant galaxy cluster yet has been discovered by combining data from NASA's Chandra X-ray Observatory and optical and infrared telescopes. The cluster is located about 10.2 billion light years away, and is observed as it was when the Universe was only about a quarter of its present age.
The galaxy cluster, known as JKCS041, beats the previous record holder by about a billion light years. Galaxy clusters are the largest gravitationally bound objects in the Universe. Finding such a large structure at this very early epoch can reveal important information about how the Universe evolved at this crucial stage.
JKCS041 is found at the cusp of when scientists think galaxy clusters can exist in the early Universe based on how long it should take for them to assemble. Therefore, studying its characteristics – such as composition, mass, and temperature – will reveal more about how the Universe took shape.
"This object is close to the distance limit expected for a galaxy cluster," said Stefano Andreon of the National Institute for Astrophysics (INAF) in Milan, Italy. "We don't think gravity can work fast enough to make galaxy clusters much earlier."...

2009 October 19. Up the Cosmic Distance Ladder. By Lee Billings, Seed Magazine. Excerpt: The development of astronomy can be seen as a millenia-long quest to measure and know the true scale of the natural world.
One of the greatest difficulties when discussing the physical world is conveying its immense scale. While we can estimate the number of molecules contained in a single drop of water (roughly 1.5 sextillion, 1,500,000,000,000,000,000,000) or measure the distance light traverses in a single second (around 300 million meters), the values we obtain are so alien that we cannot intuitively comprehend them. For most people, the difference between one and 10 is far more palpable than the difference between a thousand billion and a thousand trillion.... Few disciplines illustrate this more clearly than astronomy, the oldest of the natural sciences.
...Just how is it that we know the distance from the Earth to the Sun, the other planets, and faraway stars? How do we know the architecture and future of our galaxy or the expansion rate of the universe? The short answer is that we know these things because of the cosmic distance ladder, a suite of interdependent methods to measure successively greater distances in the universe. Though most of the ladder was created in the 20th century, millennia of effort have contributed to its construction, and it is still being refined....

2009 April 28. Most distant object in the universe spotted. By Rachel Courtland, NewScientist. Excerpt: Astronomers have spotted the most distant object yet confirmed in the universe – a self-destructing star that exploded 13.1 billion light years from Earth. It detonated just 640 million years after the big bang, around the end of the cosmic "dark ages", when the first stars and galaxies were lighting up space.
The object is a gamma-ray burst (GRB) – the brightest type of stellar explosion. GRBs occur when massive, spinning stars collapse to form black holes and spew out jets of gas at nearly the speed of light. These jets send gamma rays our way, along with "afterglows" at other wavelengths, which are produced when the jet heats up surrounding gas.
...Some of the first observations were made on Mauna Kea in Hawaii with the United Kingdom Infrared Telescope and the Gemini North telescope.
Other telescopes later measured the spectrum of the afterglow, revealing that the burst detonated about 13.1 billion light years from Earth. "It's the most distant gamma-ray burst, but it's also the most distant object in the universe overall," says Edo Berger of the Harvard-Smithsonian Center for Astrophysics, a member of the team that observed the afterglow with Gemini North.
To gauge an object's distance, astronomers measure how much an object's light has been stretched, or reddened, by the expansion of space. This burst lies at a redshift of 8.2, more distant than the previous GRB record holder, which lay at a redshift of 6.7....
...For astronomy, this is a watershed event," Joshua Bloom of the University of California, Berkeley, who observed the afterglow using the Gemini South telescope in Chile, told New Scientist."This is the beginning of the study of the universe as it was before most of the structure that we know about today came into being."...

Archive of Past Articles for Chapter 4

 

 

Chapters

  1. Cosmic Cataclysms
  2. Astronomers' Tools
  3. Cosmic Engines
  4. Fathoming Huge Distances
  5. Color, Temperature, and Age
  6. Dramatic Change in Stars
  7. Planet-Star Systems
  8. Search for Habitable Planets
  9. Cosmos Begins...and Ends?

Archive of Past Articles for All Chapters

Women in Astronomy: An Introductory Resource Guide to Materials in English. By Andrew Fraknoi (Foothill College & Astronomical Society of the Pacific)

 

5. Color, Temperature, and Age

New section

Archive of Past Articles for Chapter 5

 

 

Chapters

  1. Cosmic Cataclysms
  2. Astronomers' Tools
  3. Cosmic Engines
  4. Fathoming Huge Distances
  5. Color, Temperature, and Age
  6. Dramatic Change in Stars
  7. Planet-Star Systems
  8. Search for Habitable Planets
  9. Cosmos Begins...and Ends?

Archive of Past Articles for All Chapters

 

6. Dramatic Change in Stars

NOTICE: On the 2009 edition of the GSS CD-ROM, supernova images in the folder
ChangingCosmosImages>6FindingSupernova>snLightCurvesSN1994i
are missing. They are now posted for you to download in a zip compressed file at

snLightCurveSN1994i.zip (2.7 Mb)

2010 Feb 22. From the Clash of White Dwarfs, the Birth of a Supernova. By Dennis Overbye, NY Times. Excerpt: ...For the last 20 years, astronomers seeking to measure the cosmos have used a special type of exploding star, known as Type 1a supernovas, as distance markers. They are thought to result when stars known as white dwarfs grow beyond a certain weight limit, setting off a thermonuclear cataclysm that is not only bright enough to be seen across the universe but is also remarkably uniform from one supernova to the next. Using them, two teams of astronomers a little more than a decade ago reached the startling and now widely held conclusion that some “dark energy” was speeding up the expansion of the universe.
But astronomers, to their embarrassment, have not been able to agree on how the white dwarf gains its fatal weight and explodes, whether by slowly grabbing material from a neighboring star or by crashing into another white dwarf.
In a telephone news conference on Wednesday and a paper published Thursday in the journal Nature, Marat Gilfanov and his colleague, Akos Bogdan, both of the Max Planck Institute for Astrophysics in Garching, Germany, said that for at least one class of galaxies in the universe, the roundish conglomerations of older, redder stars known as ellipticals, these supernovas are mostly produced by collisions.
“We have revealed the source of the most important explosions in cosmology,” Dr. Gilfanov said, adding that until now “we didn’t know exactly what they were.”...

2009 Nov 6. Supernova fits into a new class. By David Perlman, Chronicle Science Editor. Excerpt: (11-05) 19:12 PST SAN FRANCISCO -- A bizarre exploding star that left its embers glowing invisibly in the distant sky .... The record examined by Dovi Poznanski, a UC Berkeley researcher, revealed that the short-lived but violent cosmic explosion in a far-off galaxy 135 million light-years away could be an entirely new class of supernovae.... This unique supernova, dubbed SN2002bj, was the first one found that was apparently caused when helium gas flowed from one tiny but immensely massive white dwarf star to another dwarf star orbiting close by. The result was a true thermonuclear explosion that died away in days rather than months, the Berkeley astronomers said, and its formation differed sharply from standard supernova models.
...Poznanski calculated that at the explosion's most powerful moment, it must have flared 10 billion times brighter than our sun, although nowhere near as bright as normal supernovae that can blaze 10 times more powerfully than that. ...The story of SN2002bj's detection actually started with a competition involving two amateur astronomers: Tim Puckett of Atlanta, who operates his own automated high-tech observatory in the little Georgia town of Ellijay (population 1,119), and Jack Newton, who has a high-tech robot telescope in Portal, Ariz. (population 80). They lead an amateur World Supernova Search Team, whose 28 members - from Canada to South Africa - use their high-powered telescopes to scan the skies every clear night. The team has discovered no fewer than 206 supernovae in the past 15 years.
Puckett and Newton discovered SN2002bj at the same time the night it flared, and immediately reported it to the International Astronomical Union's Central Bureau for Astronomical Telegrams at the Harvard Smithsonian Astrophysical Observatory in Cambridge, Mass., on April 18, 2002.
Alex Filippenko, a senior UC astronomer whose team also hunts for supernovae with a robot telescope system at Lick Observatory atop Mount Hamilton, also reported detecting the stellar explosion on the same night - but just a little later. "It really was a dead heat," Filippenko said of the discovery. But he conceded that Puckett and Newton beat him technically" by three and a half hours because Puckett's observatory is located where the time is three hours ahead and where the sun sets much earlier....

2008 November/December. Blown apart. BY KEAY DAVIDSON. Excerpt: ...Saul Perlmutter ... "Our brains are...so good at seeing patterns that we sometimes see patterns that aren't there."
Perlmutter and his colleagues have spent two decades looking for patterns in the night sky-specifically, patterns in the spatial distribution of distant, dying stars that suddenly brighten, and then fade. They hope to resolve an ancient puzzle: How will the universe end? Eleven years ago, in the autumn of 1997, they uncovered a big piece of the puzzle. But their discovery was so unexpected that they worried the patterns were illusory. They checked and rechecked their data, searching for some subtle error that might have misled them. A mistake would make them look like fools. But if they waited too long to report their results, rival teams might beat them to announcing the discovery and perhaps to winning a Nobel Prize.
Their shocking discovery was "dark energy," a mysterious repulsive force that apparently makes the universe expand faster and faster over time. Dark energy now threatens to undermine fundamental beliefs about physics, cosmology, perhaps even the nature of scientific discovery....
...when Perlmutter arrived at Berkeley as a graduate student in physics in the early 1980s, he hoped to do research "that would address a deep philosophical question." His doctoral adviser was physicist Richard A. Muller, who was planning to use robotic telescopes to look for supernovae and a hypothetical star called Nemesis, which Muller suspected triggered mass extinctions on Earth by steering comets toward the inner solar system every 26 million years. Perlmutter joined that project, where physicist Carl Pennypacker was developing a robotic telescopic search at Berkeley's Leuschner Observatory in Lafayette. Over the next few years, their hard-working robot observer detected 20 "nearby" supernovae. Although the mystery star was never found, the supernova investigations opened the long, winding road to a historic discovery....

2008 December 4. Study Illuminates Star Explosion From 16th Century. The New York Times. Excerpt: NEW YORK (AP) -- More than 400 years after Danish astronomer Tycho Brahe challenged established wisdom about the heavens by analyzing a strange new light in the sky, scientists say they've finally nailed down just what he saw.
It's no big surprise. Scientists have known the light came from a supernova, a huge star explosion. But what kind of supernova?
A new study confirms that, as expected, it was the common kind that involves the thermonuclear explosion of a white dwarf star with a nearby companion.
...The story of what's commonly called Tycho's supernova began on Nov. 11, 1572, when Brahe was astonished to see what he thought was a brilliant new star in the constellation Cassiopeia. The light eventually became as bright as Venus and could be seen for two weeks in broad daylight. After 16 months, it disappeared.
Working before telescopes were invented, Brahe documented with precision that unlike the moon and the planets, the light's position didn't move in relation to the stars. That meant it lay far beyond the moon. That was a shock to the contemporary view that the distant heavens were perfect and unchanging.
...The direct light from the supernova swept past Earth long ago. But some of it struck dust clouds in deep space, causing them to brighten. That ''light echo'' was still observable, and the new study was based on analyzing the wavelengths of light from that.
...

2008 May 21. X-RAY OUTBURST LEADS TO ALL-OUT STUDY OF SUPERNOVA. by Robert Sanders. NASA's Swift satellite caught the rare birth of a supernova earlier this year, allowing astronomers to rapidly deploy ground-based telescopes to follow its evolution and learn about normal stellar explosions. UC Berkeley astronomers have analyzed the data to conclude that the original star was more than 30 times the mass of the sun, but only slightly larger, when its core ran out of fuel and imploded, blowing the star to smithereens.

2008 May 14. DISCOVERY OF MOST RECENT SUPERNOVA IN OUR GALAXY. NASA RELEASE: 08-126. Excerpt: WASHINGTON -- The most recent supernova in our galaxy has been discovered by tracking the rapid expansion of its remains. This result, using NASA's Chandra X-ray Observatory and the National Radio Astronomy Observatory's Very Large Array, will help improve our understanding of how often supernovae explode in the Milky Way galaxy.

Archive of Past Articles for Chapter 6

 

 

Chapters

  1. Cosmic Cataclysms
  2. Astronomers' Tools
  3. Cosmic Engines
  4. Fathoming Huge Distances
  5. Color, Temperature, and Age
  6. Dramatic Change in Stars
  7. Planet-Star Systems
  8. Search for Habitable Planets
  9. Cosmos Begins...and Ends?

Archive of Past Articles for All Chapters

 

 

 

 

7. Planet-Star Systems

2011 May 25. NASA RELEASE 11-163: NASA To Launch New Science Mission To Asteroid in 2016. Excerpt: NASA will launch a spacecraft to an asteroid in 2016 and use a robotic arm to pluck samples that could better explain our solar system's formation and how life began. The mission, called Origins-Spectral Interpretation-Resource Identification-Security-Regolith Explorer, or OSIRIS-REx, will be the first U.S. mission to carry samples from an asteroid back to Earth….
…After traveling four years, OSIRIS-REx will approach the primitive, near Earth asteroid designated 1999 RQ36 in 2020. Once within three miles of the asteroid, the spacecraft will begin six months of comprehensive surface mapping. The science team then will pick a location from where the spacecraft's arm will take a sample. The spacecraft gradually will move closer to the site, and the arm will extend to collect more than two ounces of material for return to Earth in 2023….

2011 May 9. A rare direct hit from a meteorite. By Emily Lakdawalla, The Planetary Society Blog. Excerpt: Meteorites hit Earth all the time, but they almost never score direct hits on human-built structures (or humans, for that matter). Most stories you'll read on the Web about observed meteorite falls are either wrong or hoaxes. Once in a while, though, direct hits do happen, and it looks like this recent event in Poland was the real thing….
…It happened on April 30 in a rural village called Soltmany, just after 6:00 a.m. local time. A cobble-sized rock weighing about a kilogram came down nearly vertically and smashed right through a roof:
After crashing through the roof it smashed into a concrete path and broke into several pieces….
…The meteorite has a nice conical shape and an obvious fusion crust, both resulting from its high-speed descent through Earth's atmosphere; tests will be needed to make sure of its extraterrestrial origin but it's got all the right qualities to be a real meteorite….

2011 May 3. NASA RELEASE 11-133: NASA Dawn Spacecraft Reaches Milestone Approaching Asteroid. Excerpt: NASA's Dawn spacecraft has reached its official approach phase to the asteroid Vesta and will begin using cameras for the first time to aid navigation for an expected July 16 orbital encounter. The large asteroid is known as a protoplanet – a celestial body that almost formed into a planet….
…Dawn's odyssey, which will take it on a 3-billion-mile journey, began on Sept. 27, 2007, with its launch from Cape Canaveral Air Force Station in Florida. It will stay in orbit around Vesta for one year. After another long cruise phase, Dawn will arrive at its second destination, an even more massive body in the asteroid belt called Ceres, in 2015….
…The mission will compare and contrast the two giant asteroids, which were shaped by different forces. Dawn's science instrument suite will measure surface composition, topography and texture. In addition, the Dawn spacecraft will measure the tug of gravity from Vesta and Ceres to learn more about their internal structures….

2009 December. From Particles to Planets. By Kathleen M. Wong, ScienceMatters@Berkeley. Excerpt: Dust, to most of us, is nothing more than a nuisance. The grayish film that collects atop bookshelves and beneath the couch is the bane of housekeepers from Arkhangelsk to Zimbabwe. But Eugene Chiang, a Berkeley professor of astronomy and earth and planetary science, says dust deserves more respect. It is, after all, the foundation upon which entire worlds are built.
A theoretical astrophysicist, Chiang studies how planetary systems form, "starting from disks of gas and micron-sized particles in orbit around young stars, and ending with congealed objects as massive as Jupiter," he says.
How dust agglomerates into something the size of a planet remains a subject of hot debate. The trick, in terms of physics, is getting started. What mechanisms could drive specks of dust to clump in the first place? One possibility is by collisions. In this scenario, dust particles carom off one another until, by chance, a few begin to stick. But as anyone who has dropped one rock atop another knows, they easily rebound, chip, or shatter.
Chiang sees a different mechanism at play. He envisions gravity gently pulling ensembles of grains together until they coalesce into giant masses. "Grains might settle towards the midplanes of disks into a thin and dense enough layer that they can self-gravitate into objects easily kilometers in size. You jump from microns to kilometers, and then you're on your way to forming even larger objects," Chiang says.
...In the 1990s, scientists discovered that magnetic fields could brake the rotation of the gas disk and allow gas to stream inward. Chiang is investigating whether this mechanism is at play in the centers of donut-hole systems.
Magnetic fields strongly influence charged particles such as electrons and ions but have no influence on uncharged materials such as wood. By considering a wide array of chemical reactions occurring within the disk, Chiang and physics graduate student Daniel Perez-Becker are calculating how much free charge exists in young solar systems, to assess the relevance of magnetic fields.
...More fully formed solar systems hold equal allure for Chiang. In 2005, Berkeley astronomers Paul Kalas and James Graham spotted a planet circling a nearby star called Fomalhaut. Images of the planet consist of little more than a few pixels of light. Even so, Chiang was still able to deduce considerable information from them....

2009 July 21. NASA images show Jupiter apparently hit by object. Pasadena, Calif. (AP) -- Astronomers say Jupiter has apparently been struck by an object, possibly a comet. Images taken by NASA early Monday show a scar in the atmosphere near the south pole of the gas giant. The images, taken by the space agency's infrared telescope in Hawaii, come on the 15th anniversary of another comet strike. In 1994, Jupiter was bombarded by pieces of the comet Shoemaker-Levy 9. Scientists at NASA's Jet Propulsion Laboratory in Pasadena captured the new images after receiving a tip from an amateur astronomer the night before. See also:
Amateur Finds New Earth-Sized Blot on Jupiter - NASA has confirmed the discovery of a new "scar" the size of the Earth in Jupiter's atmosphere, apparently showing that the planet was hit by something large in recent days.
NASA RELEASE: 09-176. Hubble Space Telescope Captures Rare Jupiter Collision. - NASA's Hubble Space Telescope has taken the sharpest visible-light picture yet of atmospheric debris from an object that collided with Jupiter on July 19.

2009 April. Journey to Jupiter. National Geographic video -- naked science series. Ganymede has a molten core.

2009 January 16. A Better View of the Planets. By Kathleen M. Wong, ScienceMatters@Berkeley, Volume 6, Issue 40. Excerpt: What's the weather like on Jupiter? Berkeley professor of astronomy Imke de Pater knows. De Pater and her colleagues have tracked the planet's titanic and long-lasting storms, observed its icy ammonia clouds, and mapped the structure of its violent atmosphere. In other work, they've discovered methane drizzle on Saturn's moon Titan, modeled Jupiter's magnetic fields, and revealed the dynamic behavior of Neptune's skies.
...Most astronomers use ground-based telescopes to study the skies. But the drawback of viewing the cosmos from Earth is the turbulence in our atmosphere. True to her innovative style, de Pater has been pushing the limits of a newer technique known as adaptive optics (AO) to improve the quality of ground-based observations.
The method uses a reference light source near the target, such as a laser beam or adjacent moon, or in some cases the object of interest itself to quantify the degree of atmospheric turbulence, and correct the data online with help of a deformable mirror. The result: a crisp and astonishingly detailed picture.
..."If you look through a conventional telescope, you can just barely see the rings around Uranus, and you certainly don't see atmospheric details," de Pater says. By contrast, the details in her AO images of the planet rival the shots sent back by the Voyager spacecraft during its 1986 Uranus flyby....

2008 October 16. Shocking start for the solar system By Stephen G. Benka. Excerpt: In the 1970s, the hypothesis arose that our solar system was formed by a passing shock wave from a supernova, which triggered the collapse of an interstellar cloud into a dense region of gas and dust that further contracted to become the Sun and its orbiting planets. The original evidence came from very old meteorites that contained magnesium-26, a daughter product of the short-lived radioactive isotope (SLRI) aluminum-26-produced in stellar nucleosynthesis. Further evidence came from another SLRI, nickel-60, which can only be produced in a supernova's furnace. In astronomical terms, short-lived means a half-life of about a million years; any SLRIs would have been transported to, and dropped off in, the pre-solar cloud faster than that time scale. Computer modelers from the late 1990s, however, could not produce both the collapse and the injection of supernova material unless they artificially prevented the shock wave from heating the cloud. That situation has now been remedied by a group from the Carnegie Institution of Washington, who used a modern, adaptive-grid computer code with an improved treatment of heating and cooling. Their new models show that a supernova's shock wave moving into an otherwise stable solar-mass cloud can both trigger the collapse and leave behind enriched gas and dust, including the SLRIs whose products are found in meteorites. Furthermore, the researchers found that a protostar began to form in less than 200?000 years, in the blink of an astronomical eye. (A. P. Boss et al., Astrophys. J. Lett. 686, L119, 2008.)

2008 June 17. A Bounty of Midsize Planets is Reported. By Dennis Overbye, The New York Times. Excerpt: There is a lot of new territory out there in the cosmos, but nothing you would want to pitch camp on — yet.
About a third of all the Sun-like stars in our galaxy harbor modestly sized planets, according to a study announced Monday by a team of European astronomers.
At a meeting in Nantes, France, Michel Mayor of the Geneva Observatory and his group presented a list of 45 new planets, ranging in mass from slightly bigger than Earth to about twice as massive as Neptune, from a continuing survey of some 200 stars.
All of the planets orbit their stars in 50 days or less, well within the corresponding orbit of Mercury, which takes 88 days to go around the Sun, and well within frying distance of any lifelike creatures.
Dr. Mayor called the discoveries "only the tip of the iceberg" in a news release from the European Southern Observatory in Garching, Germany.
About one in 14 stars harbors a massive giant planet like Jupiter or Saturn, Dr. Mayor estimated. If in fact one in three harbors a Neptune or super-Earth, that is an appealing situation for astronomers and others who would like someday to find someplace livable or even someone living Out There.
..

Archive of Past Articles for Chapter 7

 

 

Chapters

  1. Cosmic Cataclysms
  2. Astronomers' Tools
  3. Cosmic Engines
  4. Fathoming Huge Distances
  5. Color, Temperature, and Age
  6. Dramatic Change in Stars
  7. Planet-Star Systems
  8. Search for Habitable Planets
  9. Cosmos Begins...and Ends?

Archive of Past Articles for All Chapters

http://kepler.nasa.gov
NASA's Kepler mission to find Earth size planets in the habitable zones of stars.

Asteroid visualization (YouTube) - an animation of the solar system showing asteroid discoveries starting in 1980. Earth Crossers are Red. Earth Approachers (Perihelion less than 1.3AU) are Yellow. All Others are Green.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

8. Search For Habitable Planets

In the Exoplanet Transits investigation, we are collecting image data to generate a light curves for various exoplanets:

  • images provided by the Zen Observatory, from their TrES-3 page.
  • images of GJ 436b from Bareket Observatory (Israel) on 2010 Feb 20 (85 Mb zipped). Included in the zip file is a finding chart and an image indicating where aq suitable reference star is, as well as the "check" star GJ 436).
  • The MicroObservatory project has a number of exoplanet observations. Click on their "Get Images" link, then click on "Image Archive" and look for "Other Worlds."

2009 October 19. Many More Planets Found Outside Solar System. NY Times. Excerpt: WASHINGTON(AP) -- European astronomers have found 32 new planets outside our solar system, adding evidence to the theory that the universe has many places where life could develop. Scientists using the European Southern Observatory telescope didn't find any planets quite the size of Earth or any that seemed habitable or even unusual. But their announcement increased the number of planets discovered outside the solar system to more than 400.
Six of the newly found planets are several times bigger than Earth, increasing the population of so-called super-Earths by more than 30 percent. Most planets discovered so far are far bigger, Jupiter-sized or even larger.
Two of the newly discovered planets were as small as five times the size of Earth and one was up to five times larger than Jupiter.
...What astronomers said is especially exciting is that about 40 percent of sun-like stars have planets that are closer to being Earth-sized than the size of Jupiter. Jupiter's mass is more than 300 times that of Earth's....

2009 Aug 31. A Doomed Planet, and Scientists Are Lucky to Have Spotted It. By Kenneth Chang. Excerpt: Were astronomers just lucky when they discovered the planet WASP-18b? ...about 10 times the mass of Jupiter), close to the parent star (about 1.9 million miles away, or just one-fiftieth of the distance between the Sun and Earth) and hot (3,800 degrees Fahrenheit). About one-quarter of the nearly 400 planets discovered so far have been such "hot Jupiters. But as an international team of astronomers looked more closely, they became more surprised that they had seen WASP-18b at all. The tidal forces between a star and a planet dissipate energy, and WASP-18b is so close that it should fall into its host star in less than a million years - an eye blink on the cosmic scale....

2009 July 20. Searching for Extraterrestrial Life. By Claudia Dreifus, The NY Times. Excerpt: At his day job, Alan Boss of the Carnegie Institution of Washington studies how stars and planets are born. In recent years, he has consulted with scientists for NASA’s Kepler space telescope on their mission of finding planets outside our solar system that might be hospitable to life. Mr. Boss, a 58-year-old astronomer and theoretical astrophysicist, was in New York City recently to promote his new book, “The Crowded Universe: the Search for Living Planets,” about the scientific hunt for extraterrestrial life....
Q. ON MARCH 6, A DELTA 2 ROCKET CARRYING THE KEPLER SPACE TELESCOPE WAS LAUNCHED FROM CAPE CANAVERAL. WHAT DID YOU THINK AS YOU WATCHED THE LIFTOFF?
A. Now we’re ready to do some science! The big payoff is coming!
Kepler’s mission is to detect planets outside our solar system that roughly have the same size, conditions and distance from their stars as Earth. We think the probability of finding extraterrestrial life would be best on Earth-like planets. From previous observations, we know of about 330 “extra-solar” planets. Kepler is likely to send us evidence of hundreds of Earth-like planets revolving around hundreds of Sun-like stars.
Q. YOU ARE A BIG BELIEVER IN “WE ARE NOT ALONE.” WHY?
A. From ground-based observations, we know that Earth-like planets are going to be quite common. Estimates are that “earths” probably occur in 10 to 20 percent of the stars. My feeling is that if you have that many earths and you have some prebiotic soup, comets that bring in the organic chemicals that you need to have life, something is going to grow....

2009 June 17. Exoplanet Has Oddball Orbit. By Nancy Atkinson, Universe Today. Excerpt: In what might be a evidence of planetary billiards, astronomers have found an exoplanet with an extremely odd orbit. The question is, was this planet the cue ball or the object ball? While most planets orbit around a star's mid-section, this one – called XO-3b — is tilted about 37 degrees from the star's equator. It's also a massive planet, about 10 times the size of Jupiter. Such a misalignment must have occurred as a result of a disturbance, such as a collision with another object, sometime after the planet's formation. But astronomers say they don't yet know what caused the unusual orbit of XO-3b.
...The planet was discovered back in 2007 using the transit method by measuring how the star is dimmed by the planet passing in through the line-of-sight between Earth and the star.
...But to go one step further and measure the angle of its orbit, meant that "we have to be sneaky about it," said MIT physicist Joshua Winn, who led the team that measured the planet's tilted orbit. It turns out that if a planet crosses the star's disk at an angle to the star's own rotation, it causes a distinctive pattern of change in the overall color of the star, as measured by a highly sensitive spectrograph, because of the Doppler shifts caused by the star's rotation.
...Such "hot Jupiters" ...could not have formed in the places they are seen now, according to accepted planet-formation theory. They must have formed much further out from the star, then migrated inward to their present positions. Astronomers have come up with different mechanisms to account for the migration: the gravitational attraction of other planets as they passed close by, or the attraction of the disk of dust and gas from which the star and its planets formed.
Close encounters with other planets could greatly amplify a slight initial tilt, but attraction from the disk of material could not. Likely, a cataclysmic event occurred in this planet's past....

2009 April 21. Astronomers Find Planet Closer to Size of Earth. By Dennis Overbye, The NY Times. Excerpt: European astronomers said Tuesday that they had discovered the smallest planet yet found orbiting another star. The planet could be as little as only 1.9 times as massive as the Earth and belongs to a dim red star known as Gliese 581, which lies about 20 light-years from Earth in the constellation Libra.
The star was already know to harbor at least three more massive planets. The new planet, known as Gliese 581e, is probably rocky like the Earth, but it lies in such a close orbit — only three million miles from its star — that it is surely blasted with too much radiation and heat to be livable.
...Astronomers said the discovery was more encouragement that the galaxy was full of small-mass planets and that with more time and improved instruments like the Kepler satellite, recently launched by NASA, they would eventually find Earth-like planets in orbits suitable for life around other stars.
“Finding Earth-like planets with lukewarm temperatures is the next great goal,” Geoff Marcy, of the University of California, Berkeley, a planet-hunting rival of Dr. Mayor’s, said in an e-mail message....

2009 March 2. In a Lonely Cosmos, a Hunt for Worlds Like Ours. By Dennis Overbye, The NY Times. Excerpt: ...Presently perched on a Delta 2 rocket at Cape Canaveral is a one-ton spacecraft called Kepler. If all goes well, the rocket will lift off about 10:50 Friday evening on a journey that will eventually propel Kepler into orbit around the Sun. There the spacecraft’s mission will be to discover Earth-like planets in Earth-like places — that is to say, in the not-too-cold, not-too-hot, Goldilocks zones around stars where liquid water can exist.
The job, in short, is to find places where life as we know it is possible.
“It’s not E.T., but it’s E.T.’s home,” said William Borucki, an astronomer at NASA’s Ames Research Center at Moffett Field in California, who is the lead scientist on the project. Kepler...will look for tiny variations in starlight caused by planets passing in front of their stars. Dr. Borucki and his colleagues say that Kepler could find dozens of such planets — if they exist. The point is not to find any particular planet — hold off on the covered-wagon spaceships — but to find out just how rare planets like Earth are in the cosmos.
...Kepler’s strategy is, in effect, to search for the shadows of planets. The core of the spacecraft, which carries a 55-inch-diameter telescope, is a 95-million-pixel digital camera. For three and a half years, the telescope will stare at the same patch of sky about 10 degrees, or 20 full moons, wide, in the constellations Cygnus and Lyra. It will read out the brightnesses of 100,000 stars every half-hour, looking for the telltale blips when a planet crosses in front of its star, a phenomenon known as a transit.
To detect something as small as the Earth, the measurements need to be done with a precision available only in space, away from the atmospheric turbulence that makes stars twinkle, and far from Earth so that our home world does not intrude on the view of shadow worlds in that patch of sky. It will take three or more years — until the end of Barack Obama’s current term in office — before astronomers know whether Kepler has found any distant Earths....

2008 November / December. The stars her destination. BY ROBERTA KWOK, California Alumni Magazine. A business major's epiphany leads her to become a NASA scientist. Excerpt: Natalie Batalha's worst enemy is the clock. Installed around the corner from her office at NASA Ames Research Center, a looming LED display is counting the days, hours, minutes and seconds until the launch of the Kepler Mission: NASA's first attempt to find habitable Earth-like planets in our galaxy.
"It's terrible," says Batalha '89, who has been working on the mission for eight years. "It recently rolled over from 300 to 299, and I could just feel my blood pressure rising."
When the clock runs down to zero next spring, Batalha will stand with her family at Cape Canaveral in Florida to watch Kepler's take-off. The spacecraft's telescope will peer at one slice of the sky for three-and-a-half years, to look for signs of terrestrial planets using a technique called the transit method. Batalha likens the process to a fly passing in front of a car's headlight: Every time a planet passes in front of the star it orbits, it dims the star's light a little, the same way a fly would dim a headlight as it flew past. As part of preparation for launch, Batalha has been choosing-very, very carefully-the 170,000 stars that Kepler will observe from among the 13 million in its field of view.
Batalha may be feeling the pressure, but it doesn't show. Her voice has the warm, calming quality of a public radio host, and when she demonstrates the orbit of a planet around a star, her movements are poised and exact. "Can you imagine that within your lifetime, you will probably be able to look up in the sky and say, 'That star right there has a habitable Earth-like planet orbiting it'?" asks Batalha, an associate professor at San Jose State University. "That's astounding. It's going to change the way people understand their place in the universe."....

Articles about planet finding and articles specifically about the Kepler mission may be found on the NASA Kepler mission website.

Archive of Past Articles for Chapter 8

 

Chapters

  1. Cosmic Cataclysms
  2. Astronomers' Tools
  3. Cosmic Engines
  4. Fathoming Huge Distances
  5. Color, Temperature, and Age
  6. Dramatic Change in Stars
  7. Planet-Star Systems
  8. Search for Habitable Planets
  9. Cosmos Begins...and Ends?

Archive of Past Articles for All Chapters

Transit of TrES-3, supplement for i the investigation Exoplanet Transits.

 

About Exoplanet Transits investigation:
In part I - Plot a Transit Light Curve, step C, John Kolena, HOU TRA, has found that better reference stars are at:
x = 185, y = 181 or x = 311, y = 276
rather than the one at x = 564, y = 266 (as originally suggested)

9. Cosmos Begins ... and Ends?

2008 Aug 18. The Struggle to Measure Cosmic Expansion. By DENNIS OVERBYE, NY Times. Excerpt: Hoping to understand why the universe seems to be coming apart at its seams, a young astronomer and his colleagues have embarked on one of the oldest quests in cosmology, to measure how fast the universe is growing, how big it is and how old it is. That information is encoded in the value of an elusive number known as the Hubble constant that has led astronomers on a merry chase for three-quarters of a century. "It is the most fundamental number in cosmology," said Adam Riess, 38, an astronomer at the Space Telescope Science Institute and Johns Hopkins University, and one of the discoverers 10 years ago that some kind of "dark energy" is speeding up the expansion of the universe.
This spring, in what he called "a triumph of metrology," Dr. Riess announced that he and his comrade, Lucas Macri of Texas A&M University, had used the Hubble Space Telescope to make the newest and most precise measurement yet of this parameter.
Expressed in the quaint terms astronomers favor, the Hubble constant, Dr. Riess reported, is 74 kilometers per second per megaparsec. It means that for every additional million parsecs (about 3.26 million light-years) a galaxy is from us, it is going 74 kilometers per second faster. ... with...an uncertainty of only 4.3 percent.
Only 30 years ago, distinguished astronomers could not agree within a factor of two on the value of Hubble's constant, leaving every other parameter in cosmology uncertain by at least the same factor and provoking snickers from other fields of science.
...Dr. Riess's distance ladder has only three rungs and one telescope, leaping from the Milky Way's neighborhood to supernova explosions as distant as a billion light-years.
It starts with a galaxy known as NGC 4258 (a k a Messier 106 in Ursa Major), where astronomers have found clouds emitting radio waves at a frequency characteristic of water vapor circling the center of the galaxy, as well as the all-important Cepheid stars. By tracking the speeds and motion across the sky of these clouds with high resolution radio observations, a team led by James Herrnstein of the National Radio Astronomy Observatory in Socorro, N.M., in 1999 determined its distance as 23.5 million light-years.
Knowing the distance to that galaxy allowed Dr. Riess and his team to calibrate the Cepheids, which they then used to calibrate supernovas....

2008 May. Underground Astronomy. By Kathleen M. Wong, ScienceMatters@Berkeley. Excerpt: Most scientists who study the cosmos keep their eyes fastened firmly on the sky. Not so Bernard Sadoulet. A Berkeley professor of physics, Sadoulet is stalking dark matter, the elusive material that forms the scaffolding of the universe. And the place he's laid his traps is just as shadowy-a former iron mine more than 2,300 feet underground.
Speculations about dark matter's identity range from the side effects of additional dimensions to ultralight particles known as neutrinos. But several lines of thinking have converged on heavy particles known as WIMPs (weakly interacting massive particles).
"If these particles are the dark matter, they form a dark halo around the galaxy. We are in this halo, and there are billions of these particles going through us all the time," Sadoulet says.
Sadoulet leads an experiment to find these particles within Minnesota's Soudan Mine. His Cryogenic Dark Matter Search employs detectors made of silicon or germanium crystals cooled to nearly absolute zero.
"Within five years, three totally different approaches to catching WIMPS should be in operation, and we may be at the brink of a discovery" says Sadoulet. "It's an interesting time to be searching for dark matter."

2008 Jan 4. NASA Scientists Identify Smallest Known Black Hole. NASA Release No. 08-28. Excerpt: GREENBELT, Md. - Using a new technique, two NASA scientists have identified the lightest known black hole. With a mass only about 3.8 times greater than our Sun and a diameter of only 15 miles, the black hole lies very close to the minimum size predicted for black holes that originate from dying stars.
"This black hole is really pushing the limits. For many years astronomers have wanted to know the smallest possible size of a black hole, and this little guy is a big step toward answering that question," says lead author Nikolai Shaposhnikov of NASA's Goddard Space Flight Center in Greenbelt, Md.
...lowest-mass known black hole belongs to a binary system named XTE J1650-500...

Archive of Past Articles for Chapter 9

 

 

Chapters

  1. Cosmic Cataclysms
  2. Astronomers' Tools
  3. Cosmic Engines
  4. Fathoming Huge Distances
  5. Color, Temperature, and Age
  6. Dramatic Change in Stars
  7. Planet-Star Systems
  8. Search for Habitable Planets
  9. Cosmos Begins...and Ends?

Archive of Past Articles for All Chapters

The Mysteries of the Cosmos - a panel discussion with astronomers Phil Plait, Mike Brown, Debra Fischer, Andrea Ghez, and Saul Perlmutter. Topics: newly discovered solar system objects; the black hole in our galaxy; expansion of our universe.

Please take our web survey!

GSS Home | About | Student Books | Staying Up to Date | Teacher Guides | Software | Order

Lawrence Hall of Science    © 2014 The Regents of the University of California    Contact GSS    Updated September 28, 2011