Tag: astronomy

Europe has decided to build a probe, dubbed JUICE, to study Ganymede, Callisto and Europa, Jupiter’s big icy moons.

5:31 pm

Europe has decided to build a probe to study Ganymede, Callisto and Europa, Jupiter’s big icy moons.

Known as JUICE, the Jupiter Icy Moons Explorer, the probe will enter orbit around the gas giant planet in 2030 for a series of flybys of Ganymede, Callisto and Europa. JUICE will brake into orbit around Ganymede, Jupiter’s largest moon, in 2032 for at least one year of close-up research.

Leave a comment

More problems for Dark Matter

9:29 am

Vast Polar Structure

A new study by astronomers has found a vast structure of satellite galaxies and star clusters aligned perpendicular to the Milky Way and extending outward above and below the galaxy’s nucleus by as much as a million light years.

In their effort to understand exactly what surrounds our Galaxy, the scientists used a range of sources from twentieth century photographic plates to images from the robotic telescope of the Sloan Deep Sky Survey. Using all these data they assembled a picture that includes bright ‘classical’ satellite galaxies, more recently detected fainter satellites and the younger globular clusters.

“Once we had completed our analysis, a new picture of our cosmic neighbourhood emerged”, says Pawlowski. The astronomers found that all the different objects are distributed in a plane at right angles to the galactic disk. The newly-discovered structure is huge, extending from as close as 33,000 light years to as far away as one million light years from the centre of the Galaxy.

An animation illustrating this galactic distribution is posted below the fold. You can read the actual preprint paper here.

The problem with this polar alignment with the Milky Way’s core is that the theories for explaining the distribution of dark matter do not predict it.
» Read more

Leave a comment

New data from a neutrino telescope in Antarctica had found that cosmic rays don’t come from gamma ray bursts, as had been believed by astronomers.

9:43 pm

The uncertainty of science: New data from a neutrino telescope in Antarctica has found that cosmic rays don’t come from gamma ray bursts, as had been believed by astronomers. You can read the paper here. [pdf]

Which means that astronomers at this moment have no idea what produces these high energy cosmic rays.

Leave a comment

Dark matter disappears

9:15 am

The uncertainty of science: A new study has found no evidence of dark matter within 13,000 light years of the Sun, something that had not been expected.

According to widely accepted theories, the solar neighborhood was expected to be filled with dark matter, a mysterious invisible substance that can only be detected indirectly by the gravitational force it exerts. But a new study by a team of astronomers in Chile has found that these theories just do not fit the observational facts. This may mean that attempts to directly detect dark matter particles on Earth are unlikely to be successful.

These findings will be as controversial as the now abandoned faster-than-light neutrino results last fall. Here, however, the new data is likely going to be more robust, which will cause the entire astrophysical community some real conniptions.
» Read more

4 comments

Astronomers have identified two of the oldest known stars, about 12 billion years old, both only a hundred light years away.

4:19 pm

Astronomers have identified two of the oldest known stars, about 12 billion years old, both only a hundred light years away.

What is intriguing about this discovery is that these two white dwarfs had to have formed very soon after the Big Bang, long before the Milky Way galaxy existed as we know it today. How they ended up here is an interesting puzzle.

Leave a comment

The Giant Magellan Telescope project has decided it will not participate in a funding competition offered by the National Science Foundation.

8:49 am

The 24.5 meter Giant Magellan Telescope project (GMT) has decided it is not interested in competing for funds offered by the National Science Foundation (NSF).

With just US$1.25 million available to the winner, the NSF competition was less about money and more about prestige. The NSF has been adamant that it has no significant money to support either project until the early part of next decade. But the Thirty Meter Telescope, which will still respond to the NSF’s solicitation, believed that a competition would at least demonstrate the NSF’s intention to eventually support one project — and that the winner would have an easier time attracting international partners.

But the GMT says it can go it alone, at least for now. On 23 March, the group began blasting at its mountaintop site in Chile. And they say they are nearly halfway towards raising the $700 million they need to complete construction.

If the GMT has already raised almost $350 million without NSF support, it makes perfect sense for them to thumb their noses at this piddling funding from the NSF, especially since the bureaucratic cost of getting that money will probably be far more than $1.25 million.

Leave a comment

NASA management yesterday extended funding for almost all of its on-going astrophysics missions, including Hubble, Kepler, Chandra, and Fermi.

8:37 am

NASA management yesterday extended funding for all but one of its on-going astrophysics missions, including Hubble, Kepler, Chandra, and Fermi.

According to a statement from NASA headquarters, all missions will continue in fiscal years 2013 and 2014. The guest observer programme for the Chandra X-ray Observatory would even be augmented. Only Spitzer, an infrared telescope, would be phased out earlier than the mission wanted, in 2015.

There is some justification for ending Spitzer’s funding early, as the spacecraft’s cameras have lost their ability to stay as cold as designed to do their full range of infrared observations.

Leave a comment

If there is water ice on the Moon, scientists have found that the bombardment from interstellar cosmic rays has likely caused chemical reactions that “can create complex carbon chains similar to those that help form the foundations of biological structures.”

9:11 am

Life stranger than science fiction: If there is water ice on the Moon, scientists have found that the bombardment from interstellar cosmic rays has likely caused chemical reactions that “can create complex carbon chains similar to those that help form the foundations of biological structures.”

Leave a comment

The orbit of a 150 foot wide asteroid that zipped past the Earth in February, has an orbit so much like the Earth’s that astronomer’s expect it back next year.

7:42 pm

Duck! The orbit of a 150 foot wide asteroid that zipped past the Earth in February, has an orbit that will bring it past the Earth again on February 15, 2013 by less than 15,000 miles.

The team use several automated telescopes to scan the sky, and the discovery came somewhat serendipitously after they decided to search areas of the sky where asteroids are not usually seen. “A preliminary orbit calculation shows that 2012 DA14 has a very Earth-like orbit with a period of 366.24 days, just one more day than our terrestrial year, and it ‘jumps’ inside and outside of the path of Earth two times per year,” says Jaime.

While an impact with Earth has been ruled out on the asteroid’s next visit, astronomers will use that close approach for more studies and calculate the Earth and Moon’s gravitational effects on it.

Because this newly discovered asteroid passes so close and frequently to both the Earth and Moon, astronomers will need a lot more data before they can pin down its orbit precisely, and thus predict the chances of a collision in the near future.

2 comments

The blistering hot exoplanet where it snows

4:13 pm

The blistering hot exoplanet where it snows.

These results have led to a suggestion that [HD 189733b] could continually experience silicate snow. In the lower atmosphere of [the exoplanet], magnesium silicate sublimates, that is, it passes directly from a solid into a gas. But we know there are small silicate particulates in the upper atmosphere. Formation of these particulates requires that the temperature be lowered, and so must have been formed at a temperature inversion in the atmosphere. The generally windy conditions would help some of the tiny particulates grow into respectable snow crystals.

Leave a comment

smaller planets are preferentially found in low-eccentricity orbits.

9:24 am

More Kepler results: From the abstract of a preprint paper published today on the Los Alamos astro-ph website:

The mean eccentricity of the Kepler candidates decreases with decreasing planet size indicating that smaller planets are preferentially found in low-eccentricity orbits.

In other words, the smaller a planet is, the more likely its orbit will be circular like the Earth’s. This result is encouraging news for the search for life on other worlds. Before Kepler, astronomers had found that the orbits of most exoplanets were far more eccentric than the orbits of the planets in our solar system, a condition that scientists thought was unfriendly for the development of life. These new results counter that conclusion. The orbits of the planets in our solar system might not be as unusual as first thought.

Leave a comment

JPL has issued a press release “reality check” on the impact possibilities of asteroid 2011 AG5 in 2040.

9:37 am

JPL has issued a press release “reality check” on the impact possibilities of asteroid 2011 AG5 in 2040.

“In September 2013, we have the opportunity to make additional observations of 2011 AG5 when it comes within 91 million miles (147 million kilometers) of Earth,” said Don Yeomans, manager of NASA’s Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif. “It will be an opportunity to observe this space rock and further refine its orbit. Because of the extreme rarity of an impact by a near-Earth asteroid of this size, I fully expect we will be able to significantly reduce or rule out entirely any impact probability for the foreseeable future.” Even better observations will be possible in late 2015.

In other words, we really will not know anything more about these possibilities until late next year.

Leave a comment
1 … 56 57 58 59 60 … 71