Philosophy
An event like this should humble the human species and represent a reminder that life is fragile and subject to the laws of physics.
When an object smacked into Jupiter over the weekend, giving astronomers their best cosmic-collision show since the comet Shoemaker-Levy 9 in 1994, the giant gas ball of a planet took the poke like the Pillsbury Dough Boy.
For all its scientific interest, however, the collision also serves as a stark reminder that the solar system remains a shooting gallery – with Earth, as well as Jupiter, on the wrong side of the firing line.
The object's signature on Jupiter's cloud tops initially was discovered by Australian amateur astronomer Anthony Wesley as he gathered digital images of the giant planet through his 14.5-inch telescope. After alerting other astronomers to what appeared to be a "scar" in the cloud tops similar to those generated by the pieces of Shoemaker-Levy 9, NASA scientists trained a 3-meter (9.8-foot) infrared telescope on the planet and got a good look at the scar.
"It could be the impact of a comet," according to Glenn Orton, a scientist at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., in a statement yesterday. "But we don't know for sure yet."
When it comes to objects Earthlings should keep an eye on, the catalog scientists have amassed is swelling.
Since 1995, astronomers associated with 10 search projects have discovered more than 6,200 near-Earth asteroids of all sizes, according to data from JPL. Some 784 are at least a kilometer (0.62 miles) across or larger. Just over 1,000 of the total have been deemed "potentially hazardous" – those that pass Earth at a distance of less than 4.7 million miles.
And while the biggest ones have the potential to inflict the most damage, scientists are gaining a new appreciation of the punch even small ones can deliver.
Two and a half years ago, scientists at Sandia National Laboratories in Albuquerque, N.M., conducted advanced supercomputer simulations of the June 1908 event over Siberia that flattened and scorched trees over a region 30 miles across. Estimates put the explosive clout of the air burst from either a meteor or comet fragment at between 10 and 20 megatons.
The good news: Calculations on Sandia's supercomputer, in 3-D, push that explosive yield down to between three and five megatons. The bad news: The calculations also indicated that the asteroid or comet fragment was much smaller than previously estimated. There are more small asteroids hurtling around us than large ones.
Sometimes they can seem to come out of nowhere.
Last October, astronomers detected an asteroid an estimated two to five meters across. Some 21 hours later, it entered the atmosphere over northern Sudan sprinkling the Nubian desert with meteorites. The object's blast was estimated at roughly 1,000 tons of TNT.
For asteroid specialists, this was a live-fire test of protocols they'd developed to alert astronomers to monitor the object to refine orbital and impact-location estimates – and to alert national authorities that a direct hit was on the way.
The incident "underscored the successful evolution of the Near-Earth Object Program's discovery and orbit-prediction process," wrote JPL scientists Steve Chesley, Paul Chodas, and Don Yeomans in a post-event report on the incident.
The goal, of course, is to spot these objects and produce highly refined orbit estimates in time to take defensive action, if necessary.
And what might that action look like?
In a lengthy analysis of options that earned him a newly-minted PhD in aeronautical engineering from the University of Glasgow, Joan Pau Sanchez Cuartielles sorts through several approaches ranging from detonating a small nuclear bomb near an asteroid to using a modest-sized satellite as a kind of tractor that tugs the asteroid into a less dangerous orbit, connected to the asteroid by their mutual gravity.
The stand-off nuclear option (with an explosive yield tailored to the mass and density of the asteroid) turned out to be the most effective, although politically troublesome. The gravity tug could be effective with long lead times, or if the goal is to nudge an asteroid just enough to ensure it avoids a gravitational sweet spot, or keyhole, that would put it on a collision course with Earth decades into the future.
- Grab Your Moderately Powerful Telescope...asteroid 2005 Yu55 Will Be Nearby
"Giant Asteroid to Buzz Earth Tuesday; When and How to See It" Space rock as big as 2005 YU55 hasn't gotten so close since 1976. by Ker Than November 7th, 2011 National Geographic An asteroid the size of an aircraft carrier will make a close pass...
- Earth And Asteroid 2010 Tk7
Asteroid 2010 TK7 Earth has been playing "follow the leader" with a trojan asteroid for thousands of years. The first near-Earth object other than the moon to have ever been identified, TK7 shares the same orbit as our planet but about 50 million...
- 1st Snap Of Asteroid Vesta
"NASA Dawn Spacecraft Returns Close-Up Image of Asteroid Vesta" July 18th, 2011 Jet Propulsion Laboratory NASA's Dawn spacecraft has returned the first close-up image after beginning its orbit around the giant asteroid Vesta. On Friday, July 15,...
- Asteroid Vesta Today
Image taken from a distance of about 26,000 miles (41,000 kilometers). More science here that ISS and shuttles. "NASA Spacecraft to Enter Asteroid's Orbit on July 15" Julj 15th, 2011 NASA On July 15, NASA's Dawn spacecraft will begin a prolonged...
- Fragility Of The Human Species
Physics in action...serendipitous...the point is, that such events as the one in the Yucatán some 65 million years ago and the most recent Tunguska in Siberia tend to exhibit the fragility of life on Earth. It may not be the hand of man responsible for...
Philosophy
Jupiter collision...July 2009
An event like this should humble the human species and represent a reminder that life is fragile and subject to the laws of physics.
"Jupiter collision a warning call to Earth"
The list of cosmic objects that could hit Earth is growing. Scientists study satellite 'tractors' and nuclear weapons as ways to divert asteroids headed our way.
by
Peter N. Spotts
July 22nd, 2009
The Christian Science Monitor
The list of cosmic objects that could hit Earth is growing. Scientists study satellite 'tractors' and nuclear weapons as ways to divert asteroids headed our way.
by
Peter N. Spotts
July 22nd, 2009
The Christian Science Monitor
When an object smacked into Jupiter over the weekend, giving astronomers their best cosmic-collision show since the comet Shoemaker-Levy 9 in 1994, the giant gas ball of a planet took the poke like the Pillsbury Dough Boy.
For all its scientific interest, however, the collision also serves as a stark reminder that the solar system remains a shooting gallery – with Earth, as well as Jupiter, on the wrong side of the firing line.
The object's signature on Jupiter's cloud tops initially was discovered by Australian amateur astronomer Anthony Wesley as he gathered digital images of the giant planet through his 14.5-inch telescope. After alerting other astronomers to what appeared to be a "scar" in the cloud tops similar to those generated by the pieces of Shoemaker-Levy 9, NASA scientists trained a 3-meter (9.8-foot) infrared telescope on the planet and got a good look at the scar.
"It could be the impact of a comet," according to Glenn Orton, a scientist at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., in a statement yesterday. "But we don't know for sure yet."
When it comes to objects Earthlings should keep an eye on, the catalog scientists have amassed is swelling.
Since 1995, astronomers associated with 10 search projects have discovered more than 6,200 near-Earth asteroids of all sizes, according to data from JPL. Some 784 are at least a kilometer (0.62 miles) across or larger. Just over 1,000 of the total have been deemed "potentially hazardous" – those that pass Earth at a distance of less than 4.7 million miles.
And while the biggest ones have the potential to inflict the most damage, scientists are gaining a new appreciation of the punch even small ones can deliver.
Two and a half years ago, scientists at Sandia National Laboratories in Albuquerque, N.M., conducted advanced supercomputer simulations of the June 1908 event over Siberia that flattened and scorched trees over a region 30 miles across. Estimates put the explosive clout of the air burst from either a meteor or comet fragment at between 10 and 20 megatons.
The good news: Calculations on Sandia's supercomputer, in 3-D, push that explosive yield down to between three and five megatons. The bad news: The calculations also indicated that the asteroid or comet fragment was much smaller than previously estimated. There are more small asteroids hurtling around us than large ones.
Sometimes they can seem to come out of nowhere.
Last October, astronomers detected an asteroid an estimated two to five meters across. Some 21 hours later, it entered the atmosphere over northern Sudan sprinkling the Nubian desert with meteorites. The object's blast was estimated at roughly 1,000 tons of TNT.
For asteroid specialists, this was a live-fire test of protocols they'd developed to alert astronomers to monitor the object to refine orbital and impact-location estimates – and to alert national authorities that a direct hit was on the way.
The incident "underscored the successful evolution of the Near-Earth Object Program's discovery and orbit-prediction process," wrote JPL scientists Steve Chesley, Paul Chodas, and Don Yeomans in a post-event report on the incident.
The goal, of course, is to spot these objects and produce highly refined orbit estimates in time to take defensive action, if necessary.
And what might that action look like?
In a lengthy analysis of options that earned him a newly-minted PhD in aeronautical engineering from the University of Glasgow, Joan Pau Sanchez Cuartielles sorts through several approaches ranging from detonating a small nuclear bomb near an asteroid to using a modest-sized satellite as a kind of tractor that tugs the asteroid into a less dangerous orbit, connected to the asteroid by their mutual gravity.
The stand-off nuclear option (with an explosive yield tailored to the mass and density of the asteroid) turned out to be the most effective, although politically troublesome. The gravity tug could be effective with long lead times, or if the goal is to nudge an asteroid just enough to ensure it avoids a gravitational sweet spot, or keyhole, that would put it on a collision course with Earth decades into the future.
- Grab Your Moderately Powerful Telescope...asteroid 2005 Yu55 Will Be Nearby
"Giant Asteroid to Buzz Earth Tuesday; When and How to See It" Space rock as big as 2005 YU55 hasn't gotten so close since 1976. by Ker Than November 7th, 2011 National Geographic An asteroid the size of an aircraft carrier will make a close pass...
- Earth And Asteroid 2010 Tk7
Asteroid 2010 TK7 Earth has been playing "follow the leader" with a trojan asteroid for thousands of years. The first near-Earth object other than the moon to have ever been identified, TK7 shares the same orbit as our planet but about 50 million...
- 1st Snap Of Asteroid Vesta
"NASA Dawn Spacecraft Returns Close-Up Image of Asteroid Vesta" July 18th, 2011 Jet Propulsion Laboratory NASA's Dawn spacecraft has returned the first close-up image after beginning its orbit around the giant asteroid Vesta. On Friday, July 15,...
- Asteroid Vesta Today
Image taken from a distance of about 26,000 miles (41,000 kilometers). More science here that ISS and shuttles. "NASA Spacecraft to Enter Asteroid's Orbit on July 15" Julj 15th, 2011 NASA On July 15, NASA's Dawn spacecraft will begin a prolonged...
- Fragility Of The Human Species
Physics in action...serendipitous...the point is, that such events as the one in the Yucatán some 65 million years ago and the most recent Tunguska in Siberia tend to exhibit the fragility of life on Earth. It may not be the hand of man responsible for...