The acceleration of the expansion of the universe confirmed

Via Cosmic Log:

Ten years after supernovae provided the first evidence that the expansion of the universe is accelerating, a survey of more than 10,000 galaxies has provided independent confirmation that the cosmic speed-up factor known as dark energy is for real.

Cosmic Log provides a very nice analysis of this press release from the European Organisation for Astronomical Research (ESO).

So it seems that the expansion of the universe is indeed accelerating. This means that cosmological constant is non-zero and dark energy, or some alternate explanation, is necessary to explain the observations. Our cosmology seems to be consistent and correct in terms of what is happening, we just don’t know why it is happening.

Keck images dust around nova RS Oph

The Keck Interferometer combines light very carefully from the two 10m Keck telescope to do super high resolution imaging. They can run the interferometer in “nulling” mode to remove the effects of bright stars and study the much dimmer surrounding areas. It’s complicated stuff but it looks like the technique is capable of some pretty amazing results.

In this case it looks like they got lucky and were able to catch RS Oph, a recurrent nova, in outburst. The surprise was — the dust:

The nuller saw no dust in the bright zone, presumably because the nova’s blast wave vaporized dust particles. But farther from the white dwarf, at distances starting around 20 times the Earth-sun distance, the nuller recorded the spectral chemical signature of silicate dust. The blast wave had not yet reached this zone, so the dust must have pre-dated the explosion.

“This flies in the face of what we expected. Astronomers had previously thought that nova explosions actually create dust,” said Richard Barry of Goddard, lead author of the paper on the observations that will appear in the Astrophysical Journal.

The team thinks the dust is created as the white dwarf plows through the red giant’s wind, creating a pinwheel pattern of higher-density regions that is reminiscent of galaxy spiral arms.

Novae have been studied for a long time and we thought we had them pretty much figured out. If confirmed, this result could trigger a lot of activity in the variable star community.

Viewing more of Mercury

NASA’s Messenger spacecraft flew close by Mercury on 14 January 2008. Of course, it was taking pictures and managed to give scientists views of areas of the planet not imaged when Mariner 10 flew by in 1974 and 1975. Check out this detailed image of a pockmarked Mercury. This page has links to more pictures. The flyby is described here.

This was the Messenger spacecraft’s first of three 200km high fly-bys of Mercury. The next will be October 6, 2008, and the third will be September 29, 2009. Each fly-by slows the spacecraft as it heads to orbiting Mercury in March 2011.

Astronomy talks from AAS online

The American Astronomical Society (AAS) has released the audio and video of the invited and prize lectures from their recent meeting in Austin. Furthermore, they are also making it available (eventually) via iTunes.

Kevin B. Marvel, Executive Officer

The AAS is now making the invited and prize lectures at each AAS meeting available online for those who could not attend the meeting, but would still like to benefit from the invited and prize talks.

Audio and video versions are available at:
http://aas211.showmaestro.com/

The talks will be indexed on iTunes (under podcasts) by mid-March and also available on the AAS webpage.

These are very interesting talks by notable professional astronomers. At least one of the talks is aimed at the general public but almost all of them will be interesting to amateur astronomers in some way.

Thank you AAS! Nice to see you are “getting it” when it comes to making your content widely available on the Internet.

Duck! Huge gas cloud will hit Milky Way

The BBC is reporting on an announcement from last week’s AAS meeting:

A giant cloud of hydrogen gas is racing towards a collision with the Milky Way, astronomers have announced.

Smith’s Cloud, as it is known, may set off spectacular fireworks when it smacks into our galaxy in 20-40 million years.

30 million years is tomorrow in astronomical terms. This interaction is taking place as we speak. These kinds of collisions, like our eventual collision with the Andromeda Galaxy, will keep our galaxy interesting for a very long time. In fact, it’s possible that our very existence is a result of a wave of star formation from such a collision.

So getting knocked around a bit is actually a good thing if you are a galaxy.

AAS at Astronomy Cast

Our friends Pamela Gay and Fraser Cain from Astronomy Cast, along with astronomer/sex symbol/author Phil “The Bad Astronomer” Plait have all the latest from this week’s meeting of the American Astronomical Society.

My personal favorite of their reports: Hubble Sees a Double Einstein Ring

New Podcast: Slackerpedia Galactica 8.0

We just posted a new podcast to the feed: Slackerpedia Galactica 8.0: A Brief History of the Universe. So if you subscribe to the feed, the audio is probably already on your box. Or you can check out the show notes or download the MP3 file directly:

Slackerpedia Galactica 8.0: A Brief History of the Universe (MP3, 17.2MB, 36:12)

In this show Doug and I discuss the the cosmological timeline as I wrote about in a previous post. We also talk a little about asteroid 2007 WD5 and its possible upcoming impact with Mars.

SG on facebook

Are you on facebook? If so, you can add a new, highly-useless application which lets you view a random Slackerpedia Galactica article in facebook.

I wrote this just to test out facebook’s developer API, and it has been a fun little project. There is some really funny stuff in Slackerpedia Galactica and I’m glad we can share it easily with the facebook community.

So check out Slackerpedia Galactica on facebook!