Tag: astronomy

NASA has decided that the best use for two space mirrors donated to the space agency by the National Reconnaissance Office (NRO) would be to study either dark energy and extrasolar planets.

11:04 pm

NASA has decided that the best use for two space mirrors donated to the space agency by the National Reconnaissance Office (NRO) would be to study either dark energy and extrasolar planets.

There is no funding as yet for either mission, so for the moment the mirrors will remain on the ground, in storage.

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Radar images of asteroid 1998 QE2, flying past the Earth today, show that it has its own moon.

9:05 am

Radar images of asteroid 1998 QE2, flying past the Earth today, show that it has its own moon.

When astronomers analyzed radar readings to create their first maps of 1998 QE2, the big asteroid that’s due to sail past Earth on Friday, they were surprised to find that it has a moon twice as big as an ocean liner. 1998 QE2 itself is way bigger: The latest readings from NASA’s Deep Space Network antenna in Goldstone, Calif., are consistent with earlier estimates that the asteroid is about 1.7 miles (2.7 kilometers wide). But the moon is hefty as well. Astronomers estimate its diameter at 2,000 feet (600 meters).

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Cassini has found hints of activity coming from the Saturn moon Dione.

4:26 pm

Cassini has found hints of activity coming from the Saturn moon Dione.

The spacecraft’s magnetometer has detected a faint particle stream coming from the moon, and images showed evidence for a possible liquid or slushy layer under its rock-hard ice crust. Other Cassini images have also revealed ancient, inactive fractures at Dione similar to those seen at Enceladus that currently spray water ice and organic particles.

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Not only can the very fast rotation of neutron stars sometimes speed up suddenly, scientists have now discovered that their rotation can suddenly slow as well.

12:44 pm

Not only can the very fast rotation of neutron stars sometimes speed up suddenly, scientists have now discovered that their rotation can suddenly slow as well.

The neutron star, 1E 2259+586, is located about 10,000 light-years away toward the constellation Cassiopeia. It is one of about two dozen neutron stars called magnetars, which have very powerful magnetic fields and occasionally produce high-energy explosions or pulses. Observations of X-ray pulses from 1E 2259+586 from July 2011 through mid-April 2012 indicated the magnetar’s rotation was gradually slowing from once every seven seconds, or about eight revolutions per minute. On April 28, 2012, data showed the spin rate had decreased abruptly, by 2.2 millionths of a second, and the magnetar was spinning down at a faster rate.

Astronomers had a theory which explained the sudden increase in a neutron star’s rotation. They don’t have one yet for why this star slowed.

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Scientists have released the first topo map of Titan.

4:40 pm

Scientists have released the first topo map of Titan.

Whereas Earth’s tallest mountain towers nearly 9 kilometers above sea level, Titan’s topographic variations are mild: Its highest point is just half a kilometer above the mean and its lowest just 1.7 kilometers below.

Overall the detail here is not very great. None of the instruments on Cassini can see anything smaller than a half kilometer, about 1,500 feet, so the data doesn’t really show us the rough details. Moreover, the best data is spotty, as it has been accumulated by about a hundred Cassini fly-bys, rather than systematically by an orbiting spacecraft.

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The impact of a 100 pound meteorite on the Moon in March produced the brightest flash ever recorded.

9:45 am

The impact of a 100 pound meteorite on the Moon in March produced the brightest flash ever recorded.

Anyone looking at the Moon at the moment of impact could have seen the explosion–no telescope required. For about one second, the impact site was glowing like a 4th magnitude star.

Ron Suggs, an analyst at the Marshall Space Flight Center, was the first to notice the impact in a digital video recorded by one of the monitoring program’s 14-inch telescopes. “It jumped right out at me, it was so bright,” he recalls.

The 40 kg meteoroid measuring 0.3 to 0.4 meters wide hit the Moon traveling 56,000 mph. The resulting explosion1 packed as much punch as 5 tons of TNT.

It will be really interesting to see the Lunar Reconnaissance Orbiter images of the impact site, which can’t be taken until the spacecraft passes over the site and can photograph it.

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Last Saturday the space telescope Swift detected the most powerful gamma ray bursts ever detected.

7:59 pm

Last Saturday the space telescope Swift detected the most powerful gamma ray burst ever detected.

You can see the raw reports of the detection, followed up immediately by a host of other ground-based and space-based observations at this website. Click on the circulars for GRB130427A, starting with circular 14448. When this happened last Saturday I was out camping. When I got home there were dozens of circulars to look at. Based on the data here, this gamma-ray burst was relatively close for a grb, approximately 3.6 billion light years away.

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The lingering echo of Comet Shoemaker-Levy in the atmosphere of Jupiter.

7:32 pm

The lingering echo of Comet Shoemaker-Levy in the atmosphere of Jupiter.

The Herschel observations, together with heat maps provided by NASA’s Infrared Telescope Facility on Mauna Kea, showed the researchers that the Jovian stratosphere was 20° to 30°F (10° to 15°C) warmer than it would be if completely dry. One question is whether the stratospheric warming results from the gentle, continuous infall of interplanetary dust particles, which would be warmed by sunlight as they linger high up. Cavalié and his colleagues believe IDPs create some of the infrared emission but cannot explain it all. Further, a continuously supplied source would migrate to lower depths, yet most of the emission is too high up, at pressures less than 2 millibars. And while the amount of water is roughly constant across the southern hemisphere, the emission gradually weakens northward until it’s less than half as strong. It’s not simply that Jupiter’s bottom half is hotter — there’s just more water down there. As the researchers note, “At least 95% of the observed water comes from the SL9 comet and subsequent (photo)-chemistry in Jupiter’s stratosphere according to our models, as of today.

Taken together, they conclude, these observations offer “clear evidence that a recent comet … is the principal source of water in Jupiter. What we observe today is a remnant of the oxygen delivery by the comet at 44°S in July 1994.”

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In a NASA contest, a nine-year-old has named asteroid 1999 RQ36 after the Egyptian god Bennu.

10:44 am

A rose by any other name: In a NASA contest, a nine-year-old has named asteroid 1999 RQ36 after the Egyptian god Bennu.

1999 RQ36, or Bennu, is an important asteroid for two reasons. First, NASA is sending an unmanned sample return mission to it in 2016. Second, some calculations suggest the asteroid has a 1 in a 1000 chance of hitting the Earth in 2182.

In other naming news, the private space company Uwingu has launched its “Adopt-a-Planet” campaign.

This open-ended campaign gives anyone in the public—worldwide—the opportunity to adopt exoplanets in astronomical databases via Uwingu’s web site at www.uwingu.com. Proceeds from the naming and voting will continue to help fuel new Uwingu grants to fund space exploration, research, and education.

As noted earlier, they are ignoring the IAU’s stuffy insistence that only the IAU can name things in space.

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An detailed analysis of the tumbling of the asteroid Apophis, detected by radar observations in January, suggests it will be easier to predict the asteroid’s orbit in the future.

10:15 am

The sky isn’t falling: A detailed analysis of the tumbling of the asteroid Apophis, detected by radar observations in January, suggests it will be easier to predict the asteroid’s orbit in the future.

The gentle but persistent nudging [of the Yarkovsky effect] arises when sunlight is absorbed by a rotating object and then reradiated as heat in some other direction. In particular, if Apophis were spinning retrograde (opposite the way Earth does), then over time its orbit would change in a way that increases the chance of impact in 2036. But now we can rest easy, because Apophis appears to be tumbling as it orbits the Sun. That’s the conclusion reached by a team of telescopic observers who monitored the asteroid’s light curve as it passed near Earth in January. Apophis is spinning around two axes at the same time, implying that any Sun-warmed surfaces are radiating heat in all directions, not just one in particular.

It is very difficult to measure the Yarkovsky effect, thus making it very difficult to precisely calculate the orbits of many near Earth asteroids. In the case of Apophis, however, it appears the astronomers have gotten a good handle on the problem.

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Hubble has taken a spectacular close-up image of the Horsehead Nebula.

9:46 am

A horsehead of another color: Hubble has taken a spectacular close-up image of the Horsehead Nebula.

Also, if you want to find out exactly how powerful Hubble is in comparison with both ground-based and other space telescopes, check out the video provided by this press release for the new images by the Herschel Space Telescope of the Horsehead Nebula that were also released today. Herschel, which works in the far-infrared, produces good data and information that Hubble cannot, but its imagery cannot compare.

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Using Kepler astronomers have found a solar system with five terrestrial-type planets, with two in the habitable zone.

11:23 am

Eden? Using Kepler astronomers have found a solar system with five terrestrial-type planets, with two in the habitable zone.

Using observations gathered by NASA’s Kepler Mission, the team, led by William Borucki of the NASA Ames Research Center, found five planets orbiting a Sun-like star called Kepler-62. Four of these planets are so-called super-Earths, larger than our own planet, but smaller than even the smallest ice giant planet in our Solar System. These new super-Earths have radii of 1.3, 1.4, 1.6, and 1.9 times that of Earth. In addition, one of the five was a roughly Mars-sized planet, half the size of Earth. …

The two super-Earths with radii of 1.4 and 1.6 Earth radii orbit their star at distances where they receive about 41% and 120%, respectively, of the warmth from their star that the Earth receives from the Sun. The planets are thus in the star’s habitable zone; they have the right temperatures to maintain liquid water on their surfaces and are theoretically hospitable to life.

Theoretical modeling of the super-Earth planets, Kepler-62e and Kepler-62f, suggests that both could be solid, either rocky–or rocky with frozen water.

This is big news. Additional info can be found here and here.

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A private company tells the IAU to bug off!

8:53 am

A private company tells the IAU to bug off about who has the power to name things in space!

Uwingu affirms the IAU’s right to create naming systems for astronomers But we know that the IAU has no purview—informal or official—to control popular naming of bodies in the sky or features on them, just as geographers have no purview to control people’s naming of features along hiking trails. People clearly enjoy connecting to the sky and having an input to common-use naming. We will continue to stand up for the public’s rights in this regard, and look forward to raising more grant funds for space researchers and educators this way.

The company also pointed out that even astronomers name things without the IAU’s approval.

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The International Astronomical Union has issued a press release condemning the commercial efforts of private companies to issue names for exoplanets.

11:51 am

Turf war! The International Astronomical Union has issued a press release condemning the commercial efforts of private companies to issue names for exoplanets.

Recently, an organisation has invited the public to purchase both nomination proposals for exoplanets, and rights to vote for the suggested names. In return, the purchaser receives a certificate commemorating the validity and credibility of the nomination. Such certificates are misleading, as these campaigns have no bearing on the official naming process — they will not lead to an officially-recognised exoplanet name, despite the price paid or the number of votes accrued.
… [snip]
To make this possible, the IAU acts as a single arbiter of the naming process, and is advised and supported by astronomers within different fields. As an international scientific organisation, it dissociates itself entirely from the commercial practice of selling names of planets, stars or or even “real estate” on other planets or moons. These practices will not be recognised by the IAU and their alternative naming schemes cannot be adopted.

Well la-dee-da, how dare anyone else name anything ever in space!

The truth is, the IAU was originally given this function by astronomers to coordinate the naming of obscure astronomical objects, not to provide the official names for every object and feature that will ever be discovered in space. And though the IAU does tend to favor the choices of discoverers, it has in the past also ignored their wishes. (See for example my book Genesis: the Story of Apollo 8, where the IAU rejected the names chosen by the Apollo 8 astronauts, even though those astronauts were the first to actually go and see these features.)

In the end, the names of important features in space will be chosen by those who live there.

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Despite a rest, Kepler’s problematic gyroscope is still having problems.

9:26 am

Despite a rest, Kepler’s problematic gyroscope is still having problems.

Three of the wheels are needed for Kepler’s 3.1-foot telescope to have enough sensitivity to detect the minuscule signatures of Earth-sized planets. In an exercise of caution, mission managers switched off Kepler’s reaction wheels for 10 days in January, hoping the break would redistribute lubricant inside the wheel assemblies, reducing friction and allowing the units to cool down.

But friction in wheel no. 4, which has showed friction for much of Kepler’s mission, actually increased in the month following the “wheel rest” period.

The telescope originally had four wheels. One has failed, with a second showing signs of failure. If it goes, the spacecraft will no longer be able to point with enough accuracy to do its primary mission. They might be able to use it to some observations, but its design is such that even these will be of limited value.

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The location of the volcanoes on Titan are not where scientists had expected them to be.

9:30 am

The uncertainty of science: The location of the volcanoes on Titan are not where scientists had expected them to be.

As Io moves closer to Jupiter, the planet’s powerful gravity pulls hard on the moon, deforming it. This force decreases as Io retreats, and the moon bounces back. This cycle of flexing creates friction in Io’s interior, which in turn generates enormous amounts of volcano-driving tidal heat. Common sense suggests that Io’s volcanoes would be located above the spots with the most dramatic internal heating. But Hamilton and his colleagues found that the volcanoes are significantly farther to the east than expected.

Many of the news headlines, including the article above, have trumpeted how the volcanoes on Io are in the wrong place. (See also this article.) Not. The theories were wrong, not the volcanoes. Nature does what it wants to do. It is our job to figure out why.

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Using Hubble astronomers have confirmed that it was a yellow supergiant star that was the progenitor for the nearest supernovae in decades that occurred in 2011.

9:12 am

Using Hubble astronomers have confirmed that it was a yellow supergiant star that was the progenitor for the nearest supernovae in decades, that occurred in 2011 in the Whirlpool Galaxy.

The uncertainty of science: As I noted in 2011 when the yellow supergiant was first detected in pre-explosion images. no theory at that time had ever proposed this kind of star as a supernova progenitor. The discovery has thus required the theorists to come up with new theories.

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