Category Archives: Space
I just read a story on space.com today that reports asteroid 2011 AG5 has a chance to smash into Earth in the year 2040. The asteroid was discovered in January of 2011 and was observed through September of that year. The piece of space rock is 460 feet (140 meters) wide and could pass close enough to Earth to pose a threat to us on the surface. While the odds of an impact are just 1 out of 625, any non-zero probability impact is closely monitored by the international astronomy community. On its closest pass in 2023 2011 AG5 could shave by our planet at a distance of just 0.02 astronomical units (the distance between Earth and the sun), bringing it to a close shave of just 1.86 million miles. The probability of impact is expected to decrease as scientists observe more orbits of the asteroid but it is still deserving of high levels of attention.
That got me thinking. What are some of the closest shaves, or impacts, we’ve had with asteroids? I’ve put together a list of ten asteroid collisions and near misses. Enjoy and be horrified!
10) Comet Lexell passed within 0.0151 AU (1.4 million miles) of Earth on July 1, 1770 making it the closest comet pass by the Earth
9) Asteroid 2011 MD passed by Earth at an altitude of just 7,500 mi. which is roughly the diameter of the Earth, the rock was between 10 and 45 meters and it was estimated that it would have burned up in the atmosphere and only produced a few impacting fragments
8) A meteoroid named 2011 CQ1 flew by the Earth at a staggering distance of only 3,400 miles. It was discovered on the same day as its closest pass to Earth. The rock was only four feet wide so it posed absolutely no threat to life on Earth
7) A mere two months ago asteroid 2005 YU55, a 400 meter wide rock, passed within 201,700 mi. (0.85 lunar distances)
6) Meteoroid 2008 TC3 entered Earth’s atmosphere on October 7, 2008 and exploded over the Nubian Desert in Sudan. It was the first object to be tracked as it approached the surface.
5) The event nicknamed “The Great Daylight 1972 Fireball” produced a meteoroid that passed a mere 35 miles from the Earth’s surface. The meteoroid entered the atmosphere over Utah and skipped back out over Alberta, Canada. The meteoroid was 57 meters wide and could have detonated an explosion of up to 2 kilotons had it impacted the surface.
4) 1989 FC was a 300 meter wide asteroid that passed within 0.00457 AU of Earth. While it never came within the orbital radius of the moon, it passed through the exact location of the Earth six hours earlier which drew many a sigh of relief.
3) The Barringer Crater, also known as Meteor Crater, is an impact crater in Arizona where a 50 meter meteoroid hit the planet approximately 500,000 years ago. The crater is 0.737 miles across and 570 feet deep.
2) The Tunguska Event was an extremely powerful explosion that occurred over the region of Siberia in Russia in 1908. It is believed that the explosion resulted from the airburst of a large meteoroid or comet just 3-6 miles above the surface. The fragment never hit the ground but is still regarded as an impact because it released an explosion equivalent to 10-15 megatons of TNT that was 1,000 times more powerful than the atomic bomb dropped on Hiroshima.
1) Number one simply has to be the asteroid that formed the Chicxulub Crater on the Yucatan Peninsula in Mexico 65 million years ago. The 10 kilometer wide object that hit the Earth there left an impact crater 120 miles in diameter and killed the dinosaurs and approximately 70% of life on Earth. The impact packed a punch to the tune of 96 tetratons of TNT. WOW.
Very cool news today from Virgin Galactic! This year will see the final stages of the testing for the first commercial joyride into space. Ever since the Virgin Group-backed X-Prize winning ship “Spaceship One” became the first private aircraft to reach suborbital flight, we’ve been waiting for the announcement that civilians can finally pay for a ticket to space. Virgin Galactic CEO George Whitesides said today that the two craft designed to take people to space are undergoing the final stages of their respective testing programs. The first craft, White Knight Two (WK2) has run over 75 test flights for WK2 and 16 glide flights for the actual spacecraft SpaceShipTwo. If you’re not familiar with the Virgin Galactic model of leaving the planet it has some large differences from how the boys over at NASA do it. It requires two aircraft to pull it off. The first craft, WhiteKnightTwo, is a huge jet-powered cargo plane that carries the actual spacecraft, SpaceShipTwo, under its belly. Both ascend to an altitude of about 35,000 feet before SS2 is dropped by WK2. After plunging for a few seconds WK2′s single booster engine ignites sending it into a 90° vertical climb away from the Earth. Once an altitude of 100,000 kilometers is reached the engines shut off and you’re now in space! The six passengers on board can then unbuckle and experience the weightlessness of suborbital space. When the craft is ready to descend SS2′s “feathered” wings raise to 90° to minimize the effects of re-entry while ascending through the atmosphere. Then just like the space shuttle, SS2 touches down on Space Port America’s runway in New Mexico.
The verdict from Whitesides is that final booster tests for SS2 will begin by the summer and full-scale launches will take place in the fall. If everything goes to plan (and it pretty much has so far) Virgin could be sending the first space tourists up by the spring of 2013! Virgin has already booked over 400 tickets for the first year and has collected $60 million in deposits already, representing $100 million of income. Tickets are moderately priced at $200,000 so that pretty much rules out all but the proverbial 1% from every participating in this amazing experience. But nonetheless, Virgin Galactic represents a huge milestone in humanity’s effort to expand the limits of our world and to use space in new and exciting ways. Hopefully the success of Virgin Galactic will usher in a wave to similar ventures that continue to push the envelope (and bring the price down).