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
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),
...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
...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
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
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
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
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.
DeGrasse Tyson: Death by Black Hole. Video
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
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
...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
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
..."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.,
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."
images of many types of weather/atmospheric
of Past Articles for Chapter 1
Temperature, and Age
Change in Stars
for Habitable Planets
of Past Articles for All Chapters
General Astronomy Resources
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
No one had looked at its location with an infrared
instrument until now, Clavin said....
- Astronomers' Tools
- Cosmic Engines
- Fathoming Huge
- Color, Temperature,
- Dramatic Change
- Search for Habitable
- Cosmos Begins...and
of Past Articles for All Chapters
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
1. What mechanisms drive the quasi-periodic 11-year cycle of
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
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
of Past Articles for Chapter 3
Temperature, and Age
Change in Stars
for Habitable Planets
of Past Articles for All Chapters
Fathoming Huge Distances
Rich Lohman's Asteroid
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
"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
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
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
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."...
of Past Articles for Chapter 4
Temperature, and Age
Change in Stars
for Habitable Planets
of Past Articles for All Chapters
in Astronomy: An Introductory Resource Guide
to Materials in English. By Andrew Fraknoi
(Foothill College & Astronomical Society
of the Pacific)
Color, Temperature, and Age
of Past Articles for Chapter 5
Temperature, and Age
Change in Stars
for Habitable Planets
of Past Articles for All Chapters
Dramatic Change in Stars
NOTICE: On the 2009 edition of the
GSS CD-ROM, supernova images in the
are missing. They are now posted for
you to download in a zip compressed
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
“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
...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
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
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
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
...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.
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Temperature, and Age
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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
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
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
...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
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:
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
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
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.
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
October 16. Shocking
start for the solar system By
Stephen G. Benka. Excerpt:
In the 1970s, the hypothesis
arose that our solar system was
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
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
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...
of Past Articles for Chapter 7
Temperature, and Age
Change in Stars
for Habitable Planets
of Past Articles for All Chapters
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.
Search For Habitable Planets
In the Exoplanet
we are collecting image data to generate a light curves
for various exoplanets:
provided by the Zen
Observatory, from their TrES-3
- 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
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
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
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
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
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
...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
...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
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
“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
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
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
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
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."....
about planet finding and
specifically about the Kepler mission may be found on the NASA
of Past Articles for Chapter 8
Temperature, and Age
Change in Stars
for Habitable Planets
of Past Articles for All Chapters
Transit of TrES-3, supplement
for i the investigation Exoplanet Transits.
About Exoplanet Transits
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
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
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
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,
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
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
"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.
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
of Past Articles for Chapter 9
Temperature, and Age
Change in Stars
for Habitable Planets
of Past Articles for All Chapters
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.