See other Science/Tech Articles
Title: Astronomers Warn of Looming Giant Comets
Source:
[None]
URL Source: [None]
Published: Dec 27, 2015
Author: staff
Post Date: 2015-12-27 06:00:57 by Tatarewicz
Keywords: None
Views: 74
Comments: 3
Despite our best efforts to identify potential asteroid strikes that could wreak havoc on Earth, astronomers are now warning that debris from giant comets could pose an even more dangerous threat to the planet. In an article in the Royal Astronomical Society journal, researchers explained that hundreds of massive comets have been observed in our distant solar system over the last two decades. On rare occasions when these comets enter the gravitational field of other planets, they could be deflected in the direction of Earth and, in turn, crumble into a huge field of debris due to the sun. Should such an event occur, they warn, the onslaught of debris on the planet would be devastating. "The disintegration of such giant comets would produce intermittent but prolonged periods of bombardment lasting up to 100,000 years," researchers said in the Royal Astronomical Society journal. Incredibly, the astronomers noted that the debris field from just one giant comet would surpass the mass of every near-Earth asteroid observed to date. Such events have been credited with possibly both starting life on Earth, via water and organic materials, and wiping out the dinosaurs. Just when you thought there was enough to worry about, now we've got giant comet debris fields to add to the list. Source: PhysOrg
Post Comment Private Reply Ignore Thread
Top • Page Up • Full Thread • Page Down • Bottom/Latest
#1. To: Tatarewicz (#0)
So what should we do about it?
John Howard says: There are 4 schools of economics: How to End the Refugee Flood Deflection proposals have so far included: Attaching large solar sails to divert the object with the force of the solar wind. Installing mass drivers powered by photovoltaics or nuclear power. The momentum of ejecting pieces of the object would change its course in the opposite direction. Sending a Pusher Tug spacecraft to push the object, changing its orbit enough to miss the Earth. Sending an Impactor Spacecraft to ram the object, changing its orbit enough to miss the Earth. Detonating nuclear explosives above the surface of the object to change its course. Livermore astrophysicist David Dearborn is at the Lawrence Livermore Nation Laboratory Science and Technology Principal Directorate, serving on a National Academy of Sciences research panel to evaluate methods of diverting potentially hazardous objects. He presents a strong case for using nuclear explosives. News Dec 2009 html News Dec 2009 PDF News Apr 24, 2009 html Science on Saturday lecture 2009 "Avoiding Armageddon: Diverting Asteroids with Nuclear Explosives" (UCTV First Aired: 2/8/2010 48 minutes) Available on YouTube (minute 32) or on the University of California UCTV web site. www.youtube.com/watch?v=1eOJ9doYtN0 www.uctv.tv/search-details.aspx?showID=17643 science.howstuffworks.com/asteroid-nuclear-bomb1.htm Drilling and planting nuclear explosives inside the object to break it up and change its course. (See David Dearborn links, above.) Laser Deflection could potentially respond much quicker. Firing powerful laser pulses at the object from very large lasers in space, or on a moon base, would vaporize spots on the asteroid surface. This vapor and debris would act like a rocket thruster, pushing the asteroid in the opposite direction and change its course. DANIEL D. MAZANEK at the NASA Langley Research Center in 2005 described the Comet/Asteroid Protection System (CAPS). This technique avoids the long delivery time of sending a spacecraft out to the location of the object. Provided that the moon-based or space-based laser is built ahead of time, the laser beam could begin deflecting the object within minutes. Here is a 10 page summary: http://ntrs.nasa.gov/arch....nasa.gov/20050186565.pdf Here is the longer study, written in 2005: www.nss.org/resources/lib...System%28CAPS%29-NASA.pdf Laser Deflection: Richard Fork, at the University of Alabama, describes a variation of the Laser Defection concept in 2012: www.gizmag.com/cost-effec...oid-defence-system/29199/ Laser Deflection: Professors Philip M. Lubin and Gary B. Hughes describe a variation of the Laser Defection concept in 2013: www.ia.ucsb.edu/pa/display.aspx?pkey=2943 Solar Mirrors: The Planetary Society described a concept to send spacecraft with mirrors to focus the sun's energy onto the surface of the comet. www.planetary.org/explore/projects/laser-bees/ However, because narrow beams of sunlight cannot be sent long distances like a laser, this would require the long lead time of sending spacecraft out to the vicinity of the comet or asteroid. Thus, it would not provide the rapid response time of long distance laser deflection. The "Gravity Tractor", in spite of its clever name, is technically inferior to the other proposals. 1) It requires that a very large mass be delivered to the vicinity of the asteroid and then be slowed to match the speed of the asteroid. This would require a lot of fuel to accelerate and decelerate the mass. Even more fuel would be required if the mass must be launched up from Earth. On the other hand, if the mass is not brought up from Earth, then it would need to mined from the moon or another asteroid or comet. That would cost precious time if it is not done in advance. And there would still be the large amount of fuel needed to accelerate and decelerate the mass to deliver it to the asteroid in a reasonable time. 2) After the large mass has been brought into position to hover next to the asteroid, the thrusters MUST NOT point in the direction of the asteroid, or else the particles of the exhaust would be pushing the asteroid in the direction opposite to the direction that the gravity tractor is trying to pull it. Therefore, the thrusters must point at an angle to miss the asteroid. This reduces the effective thrust vector by cosine theta, and increases the fuel requirement by 1/(cos theta). If the spacecraft is positioned further from the asteroid to narrow the theta angle, then the gravitational force to move the asteroid is reduced by 1/(r squared). In conclusion, for a given maximum payload delivered to the asteroid, the "Gravity Tractor" does less to divert the asteroid than other plans, such as a pusher tug, an impactor, or a standoff nuclear blast. An inspiring TED Talk is given by Phil Plait. www.ted.com/talks/phil_pl...fend_earth_from_asteroids He introduces some of the main points, although he misses the problems with the "Gravity Tractor", which I discuss on this page. Additional background information is being compiled on the Wikipedia page: en.wikipedia.org/wiki/Asteroid_impact_avoidance
Promises promises.
Marxism: steal everything
Keynesianism: steal by counterfeiting whenever needed
Chicago school (Milton Friedman): steal by counterfeiting at a steady, predictable rate
Austrians: don't steal
'Wiped off the Map' – The Rumor of the Century
#2. To: PnbC (#1)
Instead of spending $billions/trillions on wars for the illegal Israeli state, fund space monitoring and comet diverting stations:
#3. To: Tatarewicz (#0)
Astronomers Warn of Looming Giant Comets
Top • Page Up • Full Thread • Page Down • Bottom/Latest