New data provides further confirmation of the existence of dark energy.
Astronomers, Kepler, and SETI@home team up to find exoplanets.
Is the extrasolar planet Gliese 581d habitable? Maybe.
Private citizen has just donated $25 million for the construction of the Giant Magellan Telescope.
This is how it used to be done all the time: All the early giant telescopes built in the United States before World War II were financed by individuals or private foundations, with no or little government investment.
In mid-April the Crab Nebula erupted for six days, repeatedly emitting the most powerful flares ever recorded from the supernova remnant.
Scientists think the flares occur as the intense magnetic field near the pulsar undergoes sudden restructuring. Such changes can accelerate particles like electrons to velocities near the speed of light. As these high-speed electrons interact with the magnetic field, they emit gamma rays.
To account for the observed emission, scientists say the electrons must have energies 100 times greater than can be achieved in any particle accelerator on Earth. This makes them the highest-energy electrons known to be associated with any galactic source. Based on the rise and fall of gamma rays during the April outbursts, scientists estimate that the size of the emitting region must be comparable in size to the solar system.
Dawn captures its first image of the asteroid Vesta as it closes in on a rendezvous set for July 16.
Pop! Analysis of the images that Stardust took of Comet Tempel 1 strongly suggest that when Deep Impact hit the comet’s surface it broke open several underground cavities that then burst like balloons.
Every year, as part of its educational and research mission, the Space Telescope and Science Institute in Baltimore, Maryland holds a science symposium that focuses one of the big questions of astronomy, inviting over a hundred scientists to come and give their individual perspectives on the state of the field.
This year’s symposium ended yesterday, and the subject was the mysteries of dark matter. Though I wasn’t able to attend the symposium itself, they held a workshop for journalists yesterday, which I did attend. (You can watch the webcast here.)
So, what is dark matter?
First of all, it isn’t dark energy. Dark energy is that mysterious unknown phenomenon that is causing — on vast scales of many billions of light years — the expansion of the universe to accelerate rather than decelerate. It has nothing to do with the question of dark matter.
Second, no one knows. All that scientists do know is that objects in the outer regions of galaxies as well as the galaxies themselves don’t move at the speeds and directions expected if their known mass and gravity were the only forces influencing them. In order to successfully plot their orbits and motions, astronomers have to add a gigantic halo of extra mass, which they have dubbed “dark matter” because it is unseen, undetected, and completely invisible.
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Scientists have found evidence that a subsurface ocean of water and ammonia exists within Saturn’s moon Titan.
Dark matter: light or heavy?
Later today I will be attending press conference at a symposium on dark matter that is being held this week at the Space Telescope Science Institute in Baltimore. I will post more on this subject then.
Why is the Meathook galaxy lopsided?
More information on the asteroid “flyby” of Earth this coming November 8.
“On November 8, asteroid 2005 YU55 will fly past Earth and at its closest approach point will be about 325,000 kilometers [201,700 miles] away,” said Don Yeomans, manager of NASA’s Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif. “This asteroid is about 400 meters [1,300 feet] wide – the largest space rock we have identified that will come this close until 2028.”
Space telescopes Hubble and Swift have proven that the debris that suddenly surrounded asteroid Scheila last year was caused by a collision.
Astronomers are considering the merger two space missions to create a new optical/ultraviolet space telescope. The mission would be designed to do both deep cosmology and exoplanet observations.
The two communities would both like to see a 4–8-metre telescope in space that would cost in excess of $5 billion. “Our interests are basically aligned,” says [Jim Kasting, a planetary scientist at Pennsylvania State University]. Such a mission would compete for top billing in the next decadal survey of astronomy by the US National Academy of Sciences, due in 2020.
This story is big news, as it indicates two things. First, the 2010 Decadal Survey, released in August 2010, is almost certainly a bust. The budget problems at NASA as well as a general lack of enthusiasm among astronomers and the public for its recommendations mean that the big space missions it proposed will almost certainly not be built.
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In a paper published tonight on the Los Alamos astro-ph preprint website, astronomers described new observations of Comet Hale-Bopp at a distance of 30 astronomical units, or 2.8 billion miles, from the sun. Their conclusions:
To quote the paper, “Observing Hale-Bopp in a completely frozen state would be extremely important because a thick coma was constantly present during the entire appariation [Ed. the fly-by of the Sun]. The coma obscured the nucleus which was not observed directly. Lack photometric data of the bared nucleus, its size — one of the most important input parameter in activity models — remains uncertain.”
The best images from Solar Dynamics Observatory’s first year in space.
Scientists find a gigantic and previously unknown deposit of CO2 at Mars’ south pole.
“We already knew there is a small perennial cap of carbon-dioxide ice on top of the water ice there, but this buried deposit has about 30 times more dry ice than previously estimated,” said Roger Phillips of Southwest Research Institute in Boulder, Colo. Phillips is deputy team leader for the Mars Reconnaissance Orbiter’s Shallow Radar instrument and lead author of the report. . . . “When you include this buried deposit, Martian carbon dioxide right now is roughly half frozen and half in the atmosphere, but at other times it can be nearly all frozen or nearly all in the atmosphere,” Phillips said.
What this discovery means is that, depending on Mars’ orbital circumstances, its atmosphere can sometimes be dense enough for liquid water to flow on its surface.
Sounds crazy, but it’s true: The budget chaos at NASA has caused the ESA to halt work on its own Mars orbiter and rover.
Saturn and Enceladus linked by electricity.
Got some spare time for original science? Volunteers wanted to sift through the Kepler data to find exoplanets.
Pluto’s atmosphere is expanding, and scientists don’t know why.
Pluto travels along a highly elliptical path and last passed closest to the sun in 1989. Many planetary scientists expected the atmosphere to shrink as the icy orb began receding from the sun’s warmth. The unanticipated expansion may be related to changes in the darkness of the orb’s surface a decade or so ago, which may have caused the surface ices to absorb more solar radiation and more efficiently evaporate. Or, Greaves suggests, long-term variations in the sun’s ultraviolet output, changes linked to the roughly 11-year cycle of solar activity, may be playing a role.
An asteroid that winks.
The WISE infrared space telescope results are now online, for anyone to search.
Data from the first 57 percent of the sky surveyed is accessible through an online public archive. The complete survey, with improved data processing, will be made available in the spring of 2012. A predecessor to WISE, the Infrared Astronomical Satellite (IRAS), served a similar role about 25 years ago, and those data are still valuable to astronomers today. Likewise, the WISE legacy is expected to endure for decades.
You can hunt for new asteroids, comets, and galaxies here, with instructions on how to do it here.
The telescope that ate astronomy: More budget problems for the James Webb Space Telescope, with its launch likely delayed again until 2018.
The uncertainty of science: An underground experiment in Italy has failed to detect dark matter, as theorized by scientists.
In a paper published online last night, the XENON100 researchers report three events detected during a 100-day run of the experiment last year that might have been due to dark matter1. However, as they expected to see between 1.2 and 2.4 background events — interactions mostly caused by a radioactive contaminant in the xenon — their result is statistically negative and therefore rules out the existence of many of the more strongly interacting and heavier WIMPs.
NASA, crunched for money due to overages on James Webb Space Telescope, has cancelled its participation in the space gravitational wave mission LISA.
