Tag: astronomy

Two exoplanets disappear

4:53 pm

The uncertainty of science: Two exoplanets orbiting Gliese 581, both thought to be in the habitable zone, have now been proven to not even exist.

“We’ve proven that some of the controversial signals from Gliese 581 don’t come from two proposed Goldilocks planets, but instead are coming from activity within the star itself masquerading as planets,” lead study author Paul Robertson, an astronomer at Pennsylvania State University in University Park, told Space.com.

This result should serve as a strong reminder: Though it is likely that many if not most of the so far discovered exoplanets are real, it is also likely that many will turn out to be false positives. We won’t have solid real knowledge about them until we can actually get a close look at them, which will require far better telescopes in space, and maybe even interstellar missions to them.

Leave a comment

Telescope teamwork produces spectacular galaxy image

11:55 am

M106

Combining images from a host of space and ground-based telescopes, astronomers have created a spectacular image of the galaxy M106.

This galactic fireworks display is taking place in NGC 4258 (also known as M106), a spiral galaxy like the Milky Way. This galaxy is famous, however, for something that our Galaxy doesn’t have – two extra spiral arms that glow in X-ray, optical, and radio light. These features, or anomalous arms, are not aligned with the plane of the galaxy, but instead intersect with it.

The anomalous arms are seen in this new composite image of NGC 4258, where X-rays from NASA’s Chandra X-ray Observatory are blue, radio data from the NSF’s Karl Jansky Very Large Array are purple, optical data from NASA’s Hubble Space Telescope are yellow and blue, and infrared data from NASA’s Spitzer Space Telescope are red.

A new study of these anomalous arms made with Spitzer shows that shock waves, similar to sonic booms from supersonic planes, are heating large amounts of gas – equivalent to about 10 million Suns. What is generating these shock waves? Radio data shows that the supermassive black hole at the center of NGC 4258 is producing powerful jets of high-energy particles. Researchers thinkthat these jets strike the disk of the galaxy and generate shock waves. These shock waves, in turn, heat some of the gas – composed mainly of hydrogen molecules – to thousands of degrees.

The astronomers also used the Herschel Space Observatory to confirm the data from Spitzer.

Leave a comment

A trio of supermassive black holes

9:20 am

Astronomers have discovered a trinary of supermassive black holes at the center of a distant collision of multiple galaxies.

Astronomer Roger Deane of the University of Cape Town in South Africa and his colleagues have been watching a particular quasar, known as SDSS J1502+1115, in the constellation Boötes. Other astronomers had found that the object, located 4.3 billion light-years from Earth, possessed two supermassive black holes, each the center of a large galaxy smashing into another. The black holes are at least 24,000 light-years apart.

Deane wanted to confirm their existence, so he used an intercontinental array of radio dishes that yields even sharper views than the Hubble Space Telescope. Lo and behold, one of the black holes turned out to be two. “We were incredibly surprised,” says Deane, whose team reports its findings online today in Nature.

While the discovery of this system is incredibly cool, this article in the journal Science is surprisingly incorrect on some points, while also missing the main story.
» Read more

2 comments

Groundbreaking — the literally blasting off of a mountaintop — took place today in Chile at the eventual site of the European Extremely Large Telescope (E-ELT).

2:45 pm

Groundbreaking — the literally blasting off of a mountaintop — took place today in Chile at the eventual site of the European Extremely Large Telescope (E-ELT).

Once completed in 2024 this telescope will have a segmented mirror with a total diameter of 39 meters or 128 feet, the largest ever built.

Leave a comment

The astronomers who allocate time on the Hubble Space Telescope have decided to devote a large block for finding a Kuiper Belt object that the probe New Horizons might fly past.

5:52 pm

The astronomers who allocate time on the Hubble Space Telescope have decided to devote a large block for finding a Kuiper Belt object that the probe New Horizons might fly past.

This allocation is still contingent upon a test observation to see if Hubble will be able to spot enough objects to make the long observations worthwhile.

Leave a comment

A new analysis of Apollo lunar rocks provides strong new evidence for the theory that the Moon was formed when the Earth was hit by a Mars’ sized planet.

9:14 am

A new analysis of Apollo lunar rocks provides strong new evidence for the theory that the Moon was formed when the Earth was hit by a Mars’ sized planet.

The abstract from this just released science paper summarizes the scientific problem.

Earth formed in a series of giant impacts, and the last one made the Moon. This idea, an edifice of post-Apollo science, can explain the Moon’s globally melted silicate composition, its lack of water and iron, and its anomalously large mass and angular momentum. But the theory is seriously called to question by increasingly detailed geochemical analysis of lunar rocks. Lunar samples should be easily distinguishable from Earth, because the Moon derives mostly from the impacting planet, in standard models of the theory. But lunar rocks are the same as Earth in O, Ti, Cr, W, K, and other species, to measurement precision. Some regard this as a repudiation of the theory; others say it wants a reformation. Ideas put forward to salvage or revise it are evaluated, alongside their relationships to past models and their implications for planet formation and Earth.

The new analysis has found that lunar rocks do differ from Earth in certain ways. Not surprisingly, however, the results have uncertainties.

Leave a comment

The rupture of a drum at a nuclear waste site in New Mexico has shut down a neutrino experiment.

9:00 am

The rupture of a drum at a nuclear waste site in New Mexico has shut down a neutrino experiment.

This article, from Nature, focuses on the harm done to the science experiment, which is considerable and very unfortunate. However, scroll to the end of the article to learn a little about the drum rupture, which has serious implications for the storage of nuclear waste anywhere.

Leave a comment

The predicted new meteor shower last night was less than hoped but intriguing nonetheless.

9:18 am

The predicted new meteor shower last night was less than hoped but intriguing nonetheless.

Based on a few reports via e-mail and my own vigil of two and a half hours centered on the predicted maximum of 2 a.m. CDT (7 UT) Saturday morning the Camelopardalid meteor shower did not bring down the house. BUT it did produce some unusually slow meteors and (from my site) one exceptional fireball with a train that lasted more than 20 minutes.

One comment

On the road

6:00 am

On Thursday and Friday I will likely not be able to do much posting, as I am heading up to Kitt Peak to watch an amateur astronomer do overnight observations using the 2.1 meter telescope on the mountain. I will also be taking a tour of the numerous facilities on the mountain top. All of this is in connection with an article I am writing for Sky & Telescope.

I am unsure if I will have internet service there. If I do, I will continue to post. Otherwise I will return Friday afternoon and pick up from there.

Update, Friday mid-day: I am back. Though I had access to the internet, I was too busy with other business to post. A lot of news stories since yesterday, so there will be a lot of posts in the next few hours.

3 comments

NASA has approved a new mission for the crippled Kepler space telescope, allowing observations to continue for another two years.

9:03 am

Like a phoenix: NASA has officially approved the new mission for the crippled Kepler space telescope, allowing observations to continue for another two years.

During the K2 mission, Kepler will stare at target fields in the plane of Earth’s orbit, known as the ecliptic, during observing campaigns that last about 75 days each. In this orientation, solar radiation pressure can help balance the spacecraft, making the most of Kepler’s compromised pointing ability, team members said.

Hopefully the application of clever engineering will allow scientists to get data good enough to spot some more exoplanets.

One comment

Want to watch some astronomers blow up the top of a mountain? You can!

11:14 am

Want to watch some astronomers blow up the top of a mountain? You can!

Seriously, construction crews will in June begin blasting to prepare this mountain top in Chile for the European Extremely Large Telescope (E-ELT), a gigantic optical telescope that will have a primary mirror 39 meters or 128 feet across and is scheduled for completion sometime in the next decade. To mark the event they will be providing a live stream for everyone worldwide to watch.

Leave a comment

Rosetta photographs its target comet as it comes to life.

6:25 am

Rosetta photographs its target comet as it comes to life.

The comet 67P/Churyumov-Gerasimenko, target of ESA’s Rosetta mission, has begun to develop a dust coma. This can be seen in a series of images taken by OSIRIS, the spacecraft’s scientific imaging system, between March 27th and May 4th. In the images from the end of April, the dust that the comet is already emitting is clearly visible as an evolving coma and reaches approximately 1300 kilometers into space.

Leave a comment

Some scientists are now calling into question the BICEP2 results that confirmed the existence of inflation just after the Big Bang.

10:12 am

The uncertainty of science: Some scientists are now calling into question the BICEP2 results that confirmed the existence of inflation just after the Big Bang.

The biggest discovery in cosmology in a decade could turn out to be an experimental artifact—at least according to an Internet rumor. The team that reported the discovery is sticking by its work, however.

Eight weeks ago, researchers working with a specialized telescope at the South Pole reported the observation of pinwheel-like swirls in the polarization of the afterglow of the big bang, or cosmic microwave background (CMB). Those swirls are traces of gravitational waves rippling through the fabric of spacetime a sliver of a second after the big bang, argue researchers working with the Background Imaging of Cosmic Extragalactic Polarization 2 (BICEP2) telescope. Such waves fulfilled a prediction of a wild theory called inflation, which says that in the first 10-32 seconds, the universe underwent a mind-boggling exponential growth spurt. Many scientists hailed the result as a “smoking gun” for inflation.

However, scientists cautioned that the result would have to be scrutinized thoroughly. And now a potential problem with the BICEP analysis has emerged, says Adam Falkowski, a theoretical particle physicist at the Laboratory of Theoretical Physics of Orsay in France and author of the RĂ©sonaances blog. The BICEP researchers mapped the polarization of the CMB across a patch of sky measuring 15° by 60°. To study the CMB signal, however, they first had to subtract the “foreground” of microwaves generated by dust within our galaxy, and the BICEP team may have done that incorrectly, Falkowski reports on his blog today.

When the BICEP2 result was announced, the media went crazy over it. I however didn’t even post anything about it, as I know from experience that cosmological results such as this are very tentative and require confirmation. Too often, they turn out to be false results, with the scientists in charge fooled by the uncertain nature of their data.

The results from BICEP2 might still hold up. We need to wait a bit longer to find out.

Leave a comment

It turns out that the object dubbed G2 that is zipping past the Milky Way’s central black hole is behaving not like a cloud but more like a star.

10:24 pm

The uncertainty of science: It turns out that the object dubbed G2 that is zipping past the Milky Way’s central black hole is behaving not like a cloud but more like a star.

The latest observations by the Keck Observatory in Hawaii show that the gas cloud called “G2” was surprisingly still intact, even during its closest approach to the supermassive black hole at the center of our Milky Way galaxy. Astronomers from the UCLA Galactic Center Group reported today that observations obtained on March 19 and 20, 2014 show the object’s density was still “robust” enough to be detected. This means G2 is not just a gas cloud, but likely has a star inside.

When I wrote a piece about this object for Sky & Telescope I found that among astronomers there was great skepticism about it being just a gas cloud that would be ripped apart when it flew past the black hole. The early data was not conclusive, but enough of it suggested G2 was a star, not a cloud. It turns out here that the skeptics were right.

Leave a comment

For the first time astronomers think they have measured the rotation rate of an exoplanet, thus determining the length of its day.

9:30 am

For the first time astronomers think they have measured the rotation rate of an exoplanet, thus determining the length of its day.

Ignas Snellen and his colleagues at Leiden University in the Netherlands report in Nature1 that a gaseous planet orbiting the star β Pictoris rotates at 25 kilometres per second at its equator — faster than any planet in the Solar System and about 50 times faster than Earth. A day on the planet, called β Pictoris b, lasts just over eight hours, even though the planet has a diameter more than 16 times that of Earth’s and carries more than 3,000 times Earth’s heft.

This result falls under my category of “the uncertainty of science.” Though quite cool, and based on real data, the uncertainties are great. Don’t bet the house that this result will stand up to closer observations in the future.

One comment

The existence of a Kepler-found earth-sized planet in the habitable zone has been confirmed.

1:42 pm

Worlds without end: The existence of a Kepler-found earth-sized planet in the habitable zone has been confirmed.

The newfound planet, called Kepler-186f, was first spotted by NASA’s Kepler space telescope and circles a dim red dwarf star about 490 light-years from Earth. While the host star is dimmer than Earth’s sun and the planet is slightly bigger than Earth, the positioning of the alien world coupled with its size suggests that Kepler-186f could have water on its surface, scientists say.

In this new work, the Keck and Gemini ground-based telescopes confirmed Kepler’s discovery.

One comment
1 … 45 46 47 48 49 … 72