What’s the buzz?

As if Phil Plait didn’t have enough to do, he’s kick-starting AstronomyBuzz, a social networking site for astronomy. It allows you to share, comment on and vote on videos, photos, stories and links. Like a mini-Digg but for astronomy. Kind of cool, check it out!

A star wiggles thrice

If you are even moderately interested in astronomy you’ve heard about the latest discovery of a near-Earth-sized planet. Our buddy The Bad Astronomer lays it out very nicely for us.

The image at right shows the gravitational effect of each of the 3 planets on the star of this system. The y-axis shows the star alternately coming towards us and away from us as it orbits the barycenter of the system. (Our Sun does this too, mainly from the tug of Jupiter.) Note the units are in meters per second (m/s), this is 1/1000th of the unit astronomers generally use (km/s).

This is accomplished by measuring emission and absorption lines in the spectrum of the star. Each of these three sine waves is superimposed on the measurements. The error in these measurements is reported at about 1 m/s, so astronomers are looking for very small movements of the lines.

Thus, the trick is to first get ridiculously high-resolution observations, then measure the spectra with exquisite precision and finally untangle the influence of all of the orbiting bodies on the data. The end result of all of that work is a plot like that at right: proof that something is orbiting that star. Using other physics we can determine the masses and the size of the orbits. Even more recent technology is allowing us to probe the atmospheres of these planets spectroscopically.

I suspect there will be a lot more amazing discoveries along these lines.

Bad Transcripts

Nothing more here.

Venus Express

ESA’s Venus Express is orbiting Venus as we speak and getting some cool data and taking some cool pictures.

Venus Express was launched on 9 November 2005 from the Baikonur cosmodrome in Kazakhstan on board a Starsem Soyuz-Fregat rocket. It reached Venus about five months later, on 11 April 2006, when a delicate manoeuvre injected it into orbit around the planet. After a period of commissioning the spacecraft and the instruments, Venus Express started its nominal science operations on 4 July 2006.

The image at right is from the quoted (and linked) article at ESA. The sun break ups CO2 molecules on the daylight side and they are carried by atmospheric circulation to the night side where they combine into O2 and give off an “airglow”.

The detection of the airglow, and the capability to follow its evolution in time, is extremely important for several reasons.
“First, we can use the distribution and motion of these fluorescent O2 ‘clouds’ to understand how the atmospheric layers below move and behave,” said Giuseppe Piccioni, the other co-Principal Investigator on VIRTIS. “In this sense, the O2 airglow is a real ‘tracer’ of the atmospheric dynamics on Venus.”
“Second, the analysis of this phenomenon will provide new clues on how its global atmospheric chemistry works…

Planetary chemistry, Euro-style.

(via Ben)

A Second Stab @ Second Life

We have two new Second Life chats lined up for April! Join us for very informal cafe scientifique-style chit-chats. These are not formal talks, so anything goes!

Saturday, April 21 at 7pm EST (23UT/16SLT)
NASA CoLab
Dr. Phil Plait, as if he needs an introduction. Pshaw.
Dr. Plait will bring his skeptical mind and sharp wit to the virtual world for the first time. Maybe we can get the Cathedral of the Flying Spaghetti Monster ready for him to dedicate?
What is Second Life?
SL is an online virtual community. It’s like Everquest and World of Warcraft, except that it isn’t a “game”, has no fighting and the users create the world. It runs on Windows, Mac, and Linux. Being a user is free. You only need to pay if you want to buy land or other bells and whistles. Visit www.secondlife.com for more info and to sign up.

Both of these locations are in PG areas and should be safe for children. Screen shots and a transcript of our first chat with Dr. Stewart Lowe is available here.

Current SL users, click here for a SLURL link.
Aaron’s name is: Slacker Speedwell
Michael’s name is: Slacker Cleanslate
Feel free to add us as “friends” when you login and then join the Slacker Astronomy group.

Previous chat:

Monday, April 9 at 3pm EST (20UT/12SLT)
Slacker Astronomy Planetarium (Carmine 119, 30, 180)
Dr. Eric Chaisson, Director of the Wright Center for Science Education and Research Professor in the departments of Physics and Education at Tufts University.

Dr. Chaisson is a provocative fella who likes to tell it like it is. He is the author of the famous book, Hubble Wars, which told the behind-the-scenes story of HST’s construction and its mirror problem. His recent book, Cosmic Evolution, recent won the Kistler Book Award from the Foundation of the Future. He is also one of my two advisors at Tufts.

First Principles 2: Mass & Stuff

We have a new first principles and two new skits about McNaughty and Titan.

Show Notes are here.

Discuss in the forums here.