Meanwhile, in the cosmic shooting gallery…

From Asteroid Apocalypse at the Daily Beast:

The city of Chelyabinsk in Russia bore the brunt of the celestial fireworks. A piece of rock, about 50 feet across and weighing more than 7,000 tons, came crashing to Earth. Traveling at a blinding speed of over 40,000 miles per hour, it created a sonic boom and shock wave that shattered windows across the city: 1,200 people were injured, mainly by the flying pieces of glass, and 52 were hospitalized, 2 of them in serious condition. Chelyabinsk, once known as one of the most polluted places in the world due to its storage of nuclear waste, will now be known as “meteor city.”

The asteroid packed a huge punch, the power of 20 Hiroshima bombs. It was a “city buster,” capable of flattening a modern metropolis and reducing it to rubble. It was a miracle that the asteroid exploded roughly 10 to 15 miles above ground: had there been a ground burst, it would have caused tens of thousands of casualties. If that asteroid had hit just a few seconds later, it would have created a tragedy on Earth.

…Lurking in space are asteroids even bigger than the city busters—to wit, “nation busters” big enough to destroy Germany or England. The most dangerous one is called Apophis, which is 1,000 feet across and will come dangerously close to Earth in 2029 and again in 2036. The most recent calculations show that Apophis will barely miss Earth in 2029, but will actually graze our atmosphere. But because of the uncertainty of its path as it whizzes past, there is a small possibility that its orbit may be perturbed so it might actually hit Earth in 2036. NASA scientists are reasonably confident it will still miss Earth in 2036, but the head of the Russian space agency takes the threat of a collision seriously, stating that we have to prepare for the worst. If Apophis hits Earth, it would have the force of approximately 20,000 Hiroshima bombs.

Read on for more about this frightening subject that is also one of the most compelling arguments for a strong space program that I know of.

Steve Jurvetson took this shot at the massive Meteor Crater in Arizona. Click that link for info from NASA and check out Hiking to the bottom of Meteor Crater for more shots from Steve’s journey! His Quarries, Mines & Holes slideshow is really cool too!

Just looked at Meteor Crater and wondered how big it was. Wikipedia says that Meteor Crater aka Barringer Crater got its names from the nearby town Meteor and Daniel Barringer. From there I wandered off to read about Barringer’s actions in the early 20th century and the list of the world’s largest impact craters (this one’s just a little guy!) and the curiously tiny impact craters of the United States.

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Habitable Exoplanets

NASA’s Kepler Mission is a spacecraft observatory that scans a single large area of the sky in the constellations Cygnus and Lyra. It simultaneously measure variations in the brightness of over 100,000 stars every half hour, searching for the half hour to half a day “winks” in light output that happen when a planet transits, aka passes in front of its star. Transits are only seen when the star’s planetary system is nearly perfectly aligned with our line of sight. For a planet in an Earth-size orbit, the chance of it being aligned to produce a transit is less than 1%, and the change in light akin to the dimming of a flea crawling across a car’s headlight and viewed from several miles away. Check the videos for more of an idea of how this observatory works.

It was named in honor of Johannes Kepler, who described the motions of planets about the Sun in a precisely predictable manner. Since its launch in 2009, Kepler has confirmed over 2000 planets. If you’d like to try your hand at sifting through the Kepler data, check out planethunters.org. Also check out the Kepler Mission on Facebook, where I learned that William Borucki, science principal investigator for the Kepler mission, received the National Academy of Sciences 2013 Henry Draper Medal for founding concept and visionary leadership of the project.

Image via the Planetary Habitability Library, who have a really cool collection of projects related to extra-solar life. Image Credit: The ‘X-mas Planets’ is a collage of computer generated images of habitable worlds by the Planetary Habitability Laboratory (PHL) over an image of a section of the De Mairan’s Nebula (Messier 43) taken by the Hubble Space Telescope. Earth is at the top right. This image was done to celebrate the first year of the PHL’s Habitable Exoplanets CatalogCredit: PHL @ UPR Arecibo (phl.upr.edu), ESA/Hubble, NASA.