The upcoming rare transit of Venus is one step in a long dance among Earth, Venus and the Sun. Transits of Venus follow a peculiar pattern—two transits 8 years apart, then 105.5 years with no transits, then two transits 8 years apart, then 121.5 years with no transits, for a total cycle of 243 years—and thereby hangs a tale.
May 16, 2012 is the third martian anniversary of the start of Mars Climate Sounder (MCS) observations from Mars Reconnaissance Orbiter. MCS started measuring the atmosphere of Mars three Mars years ago, on September 24, 2006. We can now compare the weather and behavior of the atmosphere in three different years, and find the temperature differences to be surprisingly large.
Someone on Twitter pointed me to a paper recently posted to ArXiv titled "Evidence for 9 planets in the HD 10180 system." If the (tentative) conclusion holds up, HD 10180 will be the first exoplanetary system known to have more planets than our own.
Posted by Emily Lakdawalla on 2012/04/03 05:20 CDT
My notes on a two-part presentation by collaborators Jim Richardson and David Minton about the sizes of things in the Kuiper belt, a story they told by looking at Saturn's moons. How does that work? What connects Saturn's moons to the Kuiper belt is craters.
Posted by Emily Lakdawalla on 2012/03/26 02:12 CDT
One of the more exciting talks last week was given by Antoine Lucas about his work with Oded Aharonson "denoising" Cassini radar images of Titan. Cassini's radar images are superior to the camera photos in revealing fine details and topography on Titan's surface, but they do suffer from a random noise component that makes the pictures look snowy. Antoine and Oded have developed a method for removing much of this noise.
I just sat in the "small bodies" session at the Lunar and Planetary Science Conference, listening to three talks about Phobos. The first was by Abby Fraeman, who looked at data on Phobos and Deimos from the two imaging spectrometers in orbit at Mars. The next talk, by L. Chappaz, was motivated by Phobos-Grunt's mission. It asked: if you grabbed 200 grams of soil from the surface of Phobos, how much of that material would actually have originated on Mars? Then there was a particularly interesting talk that dealt with the question of how Phobos' grooves formed.
Posted by Emily Lakdawalla on 2012/03/22 10:28 CDT
Water ice at Mercury's poles? That's crazy, right? Mercury is so close to the Sun that it seems inconceivable that you could have water ice there. But Mercury's rotational axis has virtually no tilt (MESSENGER has measured its tilt to be less than 1 degree), so there are areas at Mercury's poles, most often (but not always) within polar craters, where the Sun never rises above the horizon to heat the surface.
Posted by Emily Lakdawalla on 2012/03/20 02:16 CDT
One of the topics I found most exciting yesterday was a series of talks on Titan's climate. Bob West showed how Titan's detached haze has shifted with time. Zibi Turtle presented about how Titan's weather has changed with these seasonal changes. Jason Barnes followed up Zibi's talk -- which was based on Cassini camera images -- with a study of the same regions using data from Cassini's imaging spectrometer, trying to figure out what was going on with that brightening. Ralph Lorenz talked about rainfall rates on Titan. Jeff Moore asked: what if Titan hasn't always had a thick atmosphere?
Posted by Mat Kaplan on 2012/03/06 10:18 CST
A new installment of our "Snapshots" video series examines the threat posed by asteroids on collision courses with our home planet. Emily Lakdawalla explains why it's so important to find, understand and learn to deflect these potential civilization enders.
A few times a year I find myself confronting a table full of numbers describing the orbits of things in the solar system, and cursing at myself because I've forgotten,�again, what all these numbers mean and how to manipulate them to get the particular numbers I want.
Posted by Emily Lakdawalla on 2012/02/07 05:46 CST
There's been a bit of buzz on the Web this week regarding an ESA press release titled "ESA's Mars Express radar gives strong evidence for former Mars ocean." I don't ordinarily write about press-released science papers, but am making an exception for this one
Posted by Pat Donohue on 2012/02/03 10:02 CST
Guest Post: Patrick Donohue: Six days in the crater (day one)
WhirledSol posted a cool Youtube tribute to the Planetary Society a year ago, and we just now found it! It has a nice explanation of why we are so passionate about space exploration.