Hello Space Fans,
This week we received the first images of Mercury from the MESSENGER spacecraft in orbit
around the planet. On March 29th, NASA released this image, the first of 1135 images that
came out this week.
This is the first picture taken of Mercury since Mariner 10 flew by on March 23, 1974.
The most dominant feature in this image is the crater Debussy. The radial features that
you see are due to ejecta sprayed across the surface as a meteoriod struck, exposing the
lighter-colored material underneath.
Also visible in this image is the crater Matabei. Notice how the rays coming from it are darker.
Streamers like this are rare on Mercury but it indicates that something else is under
the surface here than in the area near Debussy.
Another interesting image released this week was this color composite made from adding
together images taken with the red, green and blue filters on the camera. The extra
colors you see are from the spectral variations on the surface which are probably due to differences
in particle size,exposure times and surface features between the three filter exposures.
Finally, here's the first color image taken from orbit. This amazing hi resolution image
really highlights the sheer number of craters marking the surface of this tiny planet so
close to the Sun. Just imagine, the average surface temperature here is 400 Kelvin, and
can get as high as 700 Kelvin - that's 800 degrees Fahrenheit.
Speaking of planets, here is an amazing graphic released this week by Jason Rowe of the Kepler
Mission. You may remember that earlier this year, they announced the discovery of 1,235
candidate planets orbiting other stars.
Well, here they all are.
Depicted here are the relative sizes of the the stars the planets are orbiting along with
their colors. Shown also are the sizes of the planets in transit across the disk, which
shows their sizes really nicely.
And for comparison, they also provided the Sun with the Earth transiting.
Notice how most of the stars are comparable in size and color to the Sun, which isn't
surprising, given this is precisely the kind of thing Kepler was designed to find and measure.
Last thing, on March 30th a paper came out that extrapolates the discoveries that Kepler
has made so far and attempts to estimate the fraction of Earth like planets that might
exist in the galaxy. The answer: anywhere from 1.4 to 2.7% of all stars in the galaxy
may have an Earth-like planet orbiting it.
Which end of that range you pick depends on how you define the habitable zone. Conservative
definitions will get you closer to the 1.4 percent number.
Still, if you stick to the middle of that range and say two percent, that's a lot of
planets.
There's around 100 billion Sun like stars in the Milky Way. Two percent of that number
comes out to 2 billion. Two billion planets like the Earth.
Well that's it for now Space Fans, all links to these releases and images are in the whozit
box below, so feel free to check em out.
Thanks for watching and Keep Looking Up!