FRIENDSHIP: Today marks the 51st anniversary of Colonel John H. Glenn Jr.'s orbit around our planet in the spacecraft he called Friendship 7.
The kids and I discussed how it was a Really Big Deal, since Glenn was the first American to orbit the Earth. But we also talked about how at that point the U.S. was still viewed as playing catch up to the Soviet Union, as Yuri Garagin had orbited the Earth 10 months earlier.
Glenn's flight was different than Garagin's, in that the NASA launch was pre-announced, live coverage was widely broadcast, and all the world was watching. At his highest, Glenn was 160 miles above Earth. He made three orbits, traveling about 17,500 miles per hour, traveling 81,000 miles in all.
One thing we learned from the newsreel was that after landing and the capsule was plucked out of the ocean, Glenn actually had to exit through the escape hatch, as the primary door wouldn't open properly. You can see it for yourself here: http://www.youtube.com/watch?v=qY87RTXzA04
EXO-LENT: In week 4 of our astrobiology class through Coursera, we've been learning all about exoplanets, or planets outside of our solar system. Yesterday, we listened to two short lectures and took a quiz, and pretty much bombed it on the first taking. :/ Fortunately, by do-over time, we had reviewed and compared notes enough to score a B+, but we still felt somewhat defeated. It was the first time we'd each gotten anything less than an A.
Today, we were determined to get back on track. We listened to three lectures all about exoplanets, with much of the discussion being about biosignatures, or any substance used to prove past or present life. Astrobiologists use telescopes to search for biosignatures as a tool to remotely detect the spectra of planetary atmospheres. For instance, scientists study the infrared spectra being radiated by an exoplanet and look for absorption troughs or dips caused by particular gases (carbon dioxide, oxygen, ozone, etc.) . For obvious reasons, it can be hard to detect the light spectra being given off by exoplanets given they are so distant, and if they're close to their star, the star's light can overcome the planet's biosignature spectrum. And the smaller the planet is, the tougher it is to spot.
The last of three lectures we watched today covered missions to search for biosignatures. The Hubble Space Telescope discovered the first exoplanet in 2001. In 2003, the Spitzer Space Telescope found its first exoplanet.
In 2006, the French/European Space Agency mission COROT used the transit method to find am exoplanet (COROT 7B)
The Kepler has found the most exoplanets - more then 50 additional ones. It was big news in 2001 when it found two Earth sized planets orbiting a star like our own. In January of this year, NASA announced Kepler had spotted 461 new planet candidates.
Right after we took the quiz, I showed the kids a NASA press release I'd received via email earlier in the day. it was all about Kepler and exoplanets!
Today's big news was that Kepler mission scientists have discovered a new planetary system home to the smallest planet yet found around a star similar to our sun.
Per the release, "The planets are located in a system called Kepler-37, about 210 light-years from Earth in the constellation Lyra. The smallest planet, Kepler-37b, is slightly larger than our moon, measuring about one-third the size of Earth. It is smaller than Mercury, which made its detection a challenge. The moon-size planet and its two companion planets were found by scientists with NASA's Kepler mission, which is designed to find Earth-sized planets in or near the 'habitable zone,' the region in a planetary system where liquid water might exist on the surface of an orbiting planet."
While Kepler-37b is intriguing to be sure, astronomers don't believe it to have an atmosphere capable of supporting life as we know it. In the NASA graphic above, Kepler-37c is slightly smaller than Venus, measuring almost three-quarters the size of Earth. Kepler-37d, the farther planet, is twice the size of Earth.
The star around which Kepler-37b, c, and d orbit is in the same class as our sun, but it's slightly cooler and smaller. However, since the three Kepler planets shown above all orbit that star at less than the distance Mercury is to our sun, it's a safe assumption that each in the Kepler trio is a hot, inhospitable worlds.
So today was yet another example of how our astrobiology course has immediately helped us understand news we encounter in our daily 'travels.'
BIG DIG: At noon, we listened in on a JPL teleconference all about the latest, greatest news from Mars Science Laboratory. NASA's Mars rover Curiosity has relayed new images that confirm it has successfully obtained the first sample ever collected from the interior of a rock on another planet. It's a ground breaking announcement literally, as no rover has ever has drilled into a rock beyond Earth and collected a sample from its interior.
Image Credit: NASA/JPL-Caltech/MSSS
The image (taken on Mars, today!) above shows the sample, now in the rover's scoop, which was extracted by the drill. Next up: the sample will be sieved, and portions of it delivered to the Chemistry and Mineralogy instrument and the Sample Analysis at Mars instrument.