This Week in Space – August 27, 2010
I was a bit busy last week and wasn’t able to do one of the things I really wanted to: write about space and a few extraordinary developments that have been announced or released lately. Namely, there’s been more fun with exo-planetary systems, Europa and asteroids.
F-Yeah Exo-Planetary Systems
A few months ago I wrote about the discovery of a hot “near-Earth” named GJ 1214b. The rocky planet measuring about six times the mass of the Earth was discovered at about 40 light years distance using the Radial Velocity method of exo-planetary detection (measuring red-shift of a star to determine slight wobbles caused by a star — in this case, GJ 1214 — orbiting along with exo-planet(s) around their common center of gravity).
Scientists at a conference in France announced this week the discovery of two new exciting sets of exo-planetary systems, each distinguishing in its own way. The first, which has been observed primarily using Radial Velocity is the discovery of the stellar system with the most known planets outside of our own solar system. HD 10180, a Sun-like M-Class star sitting about 128 light years away hosts a whopping seven planets.
NASA released the above animation of the planetary system around HD 10180.
Click through for more discussion and discovery.
For those forgetting, Pluto has been downgraded to join in the category of “dwarf planet” — non-satellite celestial bodies that are significant enough in size to have accretion, but lacking sufficient mass to clear their orbits. So while Pluto left the planetary eight to join Ceres, Haumea, Makemake and Eris in the lesser category, we still have Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
HD 10180 is orbited by five solidly confirmed planets (designated 10180c through g) and two unconfirmed planets (a near-Earth-sized planet right up against the star and a Saturn-sized planet 3.5 AU off, designated 10180b and h, respectively). What makes the planetary system remarkable is the degree to which its planets have fallen into standard orbits, lacking any major eccentricities that are likely to cause disruptive interactions. In other words, this is a stable planetary system that qualifies as the first discovered system where one could imagine the planets clearing the debris ring and establishing a somewhat hospitable plane, even if none of the planets actually are of sufficient type and in the Goldilocks zone so as to permit Earth-like (read, life-friendly) conditions.
The second is maybe more exciting. Using the new Kepler Space Telescope to conduct Transit Method observation (observing the faint dimming of light from a star as its exo-planet(s) “transit” — or partially eclipse from our perspective as they move in front of — the star during their orbits), scientists observed a system which they confirmed had two “Saturn-like” planets that travel in orbits of approximately 19 and 39 Earth days. Faint, unconfirmed dimming hinted that a rocky super-Earth orbits in approximately 1.6 days. The results and observations were also verified using back-up, Radian Velocity data, but the key was this was the first time that Kepler got to really flex its muscles.
The star system discovered by Kepler and named Kepler-9 is about 22,800 light years away and hosts a Sun-like, M-Class star named KIC 3323887. Never before had the Transit Method been used (along with the scientific trick of Transit Timing to confirm that the transits are, in fact, of planets and not dwarf stars) to identify a multiple-exo-planetary system. Furthermore, the sophisticated measurement of minor orbital period variations permitted the scientists to gauge the actual radii and orbital patterns of the planets. Later work using Radial Velocity confirmed their masses.
The New York Times published a very cool interactive infographic about Kepler in March 2009. The infographic provides a good bit of information on Kepler and can be seen here.
Lets Go To Europa Already
One of my other favorite space topics is Europa. I wrote about the discovery of evidence that its sub-glacial oceans are more oxygenated than previously believed almost a year ago in one of my first blog posts. While Enceladus and Titan may rival Europa for “most exciting satellite” in our solar system, the Galilean moon of Jupiter is probably the best bet for evidence of life outside of maybe Mars (and the Earth, of course).
The problem is that exploring Europa ain’t easy. The entire planet is encased in an iceball that is anywhere from 10 meters to 100 kilometers thick, covering a liquid water ocean believed to contain more H20 than the planet Earth. Getting from the surface to the exciting, possibly life-harboring ocean would require traversing the glacial shell.
And that’s if you can get to Europa. It’s a five-year trek to a Jovian orbit and landing on a satellite for such a distant body isn’t easy, particularly when you have to assess your landing site from one of many orbits, as has been suggested by Cornell PhD candidate Joseph Shoer, who has posted a sophisticated look at how one might plan to explore the icy planet. Hint: very carefully and thoughtfully, with a focus on the large fractures of ice where tidal forces create brief, periodic gaps to the ocean below.
Shoer has designed a theoretical lander and probe system, which space vehicle would have a far shorter lifespan than everyone’s Pixar-style hero, Spirit (and it’s less celebrated twin Opportunity gets no love from this blog). Although his drawings are a bit crude, his concept works and is likely a good starting point to be mulled over at the Jet Propulsion Laboratory for when they finally do push forward toward a Galilean mission.
While the likelihood of a Europa mission coming soon isn’t really strong, it doesn’t mean we can’t hope and dream. After all, that’s what space is all about.
Pray for Rain… And no Apophis
I’m going to close with a horrifying and magnificently beautiful animation, uploaded to YouTube by user szyzyg and rendered from data sets collected by Ted Boswell at NAIC. The rendering is an animation of the discovery of asteroids in our solar system between 1980 and 2010.
The most striking thing about the animation is hard to gather. There really are three things that stand out:
- The discovery of Asteroids is hardly uniform… it happens in bunches;
- Wow, we’re in a shooting gallery, and yet are amazingly safe; and
- Dang it is fascinating to watch the influence of the planetary bodies, especially Mars, on the surrounding Kuiper Belt objects and the planetary crossers.
The coloring of the objects is a bit distracting and makes one think space that really is quite empty is far more full than it is (remember, these objects are really a pixel in size at this scale… they’re far smaller than the pale blue dot which wasn’t even a pixel on Sagan’s Voyager portrait of the solar system). But you should pay heed to the colors. Green asteroids are in the safe zone. Earth approachers (meaning they come close to, but don’t threaten Earth in their current projections) are in yellow. The red asteroids are the objects that we have to worry about: the Earth Crossers including 99942 Apophis. Eventually, one of these will collide with the Earth… thankfully, not likely in our lifetime (at least none that we’ve discovered so far), unless Apophis hits that keyhole. If it doesn’t we just have to wait for 1999 RQ36 in 2182.