2012 April 16 Monday
Neil deGrasse Tyson On Why We Should Avoid Extinction

If we get wiped out by a large asteroid strike all the other intelligent species in the galaxy will laugh at our extinct selves.

If humans one day become extinct from a catastrophic collision, we would be the laughing stock of aliens in the galaxy, for having a large brain and a space program, yet we met the same fate as that pea-brained, space program-less dinosaurs that came before us.

Yes, we really should try to avoid becoming the laughing stock of the galaxy.

I bet all the species that have defeated aging and developed the means to keep themselves always youthful are laughing at us for allowing ourselves to grow old and die too.

By Randall Parker    2012 April 16 10:25 PM   Entry Permalink | Comments (17)
2011 October 20 Thursday
Scientists Model Chicxulub Meteorite Impact

When a massive meteorite hit the Earth 65 million years ago how big was its effects? Princeton researchers have developed a better model for simulating the effects of a large meteorite impact.

Seeking to better understand the level of death and destruction that would result from a large meteorite striking the Earth, Princeton University researchers have developed a new model that can not only more accurately simulate the seismic fallout of such an impact, but also help reveal new information about the surface and interior of planets based on past collisions.

Princeton researchers created the first model to take into account Earth's elliptical shape, surface features and ocean depths in simulations of how seismic waves generated by a meteorite collision would spread across and within the planet. Current projections rely on models of a featureless spherical world with nothing to disrupt the meteorite's impact, the researchers report in the October issue of Geophysical Journal International.

The researchers -- based in the laboratory of Jeroen Tromp, the Blair Professor of Geology in Princeton's Department of Geosciences -- simulated the meteorite strike that caused the Chicxulub crater in Mexico, an impact 2 million times more powerful than a hydrogen bomb that many scientists believe triggered the mass extinction of the dinosaurs 65 million years ago. The team's rendering of the planet showed that the impact's seismic waves would be scattered and unfocused, resulting in less severe ground displacement, tsunamis, and seismic and volcanic activity than previously theorized.

2 million times more powerful than a hydrogen bomb is pretty extreme.

On the bright side, the researchers do not think a Chicxulub-sized impact would unleash the scale of volcanic eruption that would basically wipe out huge numbers of species.

"Regarding the mass extinction, we saw from our measurements that a Chicxulub-sized impact alone would be too small to cause such a large volcanic eruption as what occurred at the Deccan Traps. Our model shows that the antipodal focusing of the seismic wave from such an impact was hugely overestimated in previous calculations, which used a spherical-Earth model.

"The Earth's maximum ground displacement at this point has been calculated to be 15 meters, which is extreme. The first outcome of our model was that this is reduced by a large amount to about three to five meters. On the spherical model, all the waves come together at exactly one point and, as a result, have a huge amplitude. We found the waves are disturbed by surface features and take on a more ragged structure, meaning less energy is concentrated at the antipode.

Still, surviving such an impact would not be easy. The ground movements and potentially huge ocean waves would combine with a big shock wave in the atmosphere and reduced sunlight afterward.

We need to find all the large objects that might strike the Earth and see if any will hit us any time this century. Then prepare accordingly.

By Randall Parker    2011 October 20 09:34 PM   Entry Permalink | Comments (17)
2010 January 22 Friday
US Spends Only $4 Million Per Year On Asteroid Detection

Chump change.

WASHINGTON -- A new report from the National Research Council lays out options NASA could follow to detect more near-Earth objects (NEOs) – asteroids and comets that could pose a hazard if they cross Earth's orbit. The report says the $4 million the U.S. spends annually to search for NEOs is insufficient to meet a congressionally mandated requirement to detect NEOs that could threaten Earth.

An asteroid could wipe out human civilization. Surely the threat warrants more than $4 million per year to detect a large asteroid or comet on a collision course with Earth.

Congress said go find potential threats. But didn't legislate the money to do the job.

Congress mandated in 2005 that NASA discover 90 percent of NEOs whose diameter is 140 meters or greater by 2020, and asked the National Research Council in 2008 to form a committee to determine the optimum approach to doing so. In an interim report released last year, the committee concluded that it was impossible for NASA to meet that goal, since Congress has not appropriated new funds for the survey nor has the administration asked for them.

A faster search is best done with space telescopes. But ground telescopes can also play an important role at lower cost.

In its final report, the committee lays out two approaches that would allow NASA to complete its goal soon after the 2020 deadline; the approach chosen would depend on the priority policymakers attach to spotting NEOs. If finishing NASA's survey as close as possible to the original 2020 deadline is considered most important, a mission using a space-based telescope conducted in concert with observations from a suitable ground-based telescope is the best approach, the report says. If conserving costs is deemed most important, the use of a ground-based telescope only is preferable.

I'd rather build up ground and space search capabilities than spend more on putting humans on a space station or to send more probes to the outer planets. I would also put asteroid search ahead of many other government programs in priority. How about you?

By Randall Parker    2010 January 22 09:36 PM   Entry Permalink | Comments (10)
2009 December 16 Wednesday
Diplomatic Problem With Asteroid Deflection

Former astronaut Rusty Schweickart’s group for promoting the development of asteroid defenses points out a curious problem: While an asteroid would be in the process of getting deflected its aim would shift across the planet Earth. Countries would oppose an asteroid's collision path cross over their territory while it was in the process of being re-aimed to miss Earth entirely.

Schweickart’s group, The B612 Foundation, has advocated a different approach to asteroid deflection, but one that will require an equally difficult international negotiation. They propose to bump or tow an asteroid “in a controlled manner” so that it misses Earth. The only problem is that such a process would take time and as the asteroid’s trajectory changed, it would be “pointed” at different places along a horizontal plane on Earth called the risk corridor.

I think we ought to put more effort into discovering all the asteroids out there. I'd prefer to know when one is going to hit and then have the diplomatic problem of how to deflect it rather than discover it was going to hit 3 days before it got here.

By Randall Parker    2009 December 16 11:50 PM   Entry Permalink | Comments (27)
2009 October 27 Tuesday
Asteroid Over Indonesia Triple Hiroshima Bomb Power

An asteroid over Indonesia exploded too high up to cause ground damage but with enormous force.

On 8 October an asteroid detonated high in the atmosphere above South Sulawesi, Indonesia, releasing about as much energy as 50,000 tons of TNT, according to a NASA estimate released on Friday. That's about three times more powerful than the atomic bomb that levelled Hiroshima, making it one of the largest asteroid explosions ever observed.

No telescope spotted it before it entered Earth's atmosphere. Rather than try to return to the Moon or go to Mars I would rather build an asteroid defense system. My motto: First, don't die.

By Randall Parker    2009 October 27 12:35 AM   Entry Permalink | Comments (3)
2009 October 04 Sunday
Microorganisms Bounced Back Quicker At K-T Boundary

At the Cretaceous-Tertiary (K-T) boundary of mass species extinctions the microorganisms bounced back sooner than previously thought.

In 1980, Luis Alvarez and his collaborators stunned the world with their discovery that an asteroid impact 65 million years ago probably killed off the dinosaurs and much of the the world's living organisms. But ever since, there has been an ongoing debate about how long it took for life to return to the devastated planet and for ecosystems to bounce back.

I haven't kept up with the Cretaceous-Tertiary (K-T) boundary extinction debate. But some scientists argue the Chicxulub asterioid impact predates the K-T boundary by a few hundred thousand years. Has that paper stood the test of time? Massive volcanic eruptions are cited as another potential cause of the extinctions. Anyone know what the state of play is in that debate?

Whether or not an asteroid impact caused the K-T extinctions an asteroid impact as big as the Chicxulub impact could wipe out humanity. It strikes me we should pay attention to the past and potential future causes of mass extinctions. I do not want the human race to go extinct. I think we've got to make a conscious effort to avoid extinction. We need to better understand extinction events (including the one we are causing right now in other species) and try to avoid that fate.

Microorganisms can bounce back pretty quickly.

Now, researchers from MIT and their collaborators have found that at least some forms of microscopic marine life — the so called "primary producers," or photosynthetic organisms such as algae and cyanobacteria in the ocean — recovered within about a century after the mass extinction. Previous research had indicated the process might have taken millions of years.

Well great for algae and cyanobacteria. They were only down for a century before recovering. But what does that tell you about the scope of a really big asteriod impact? Forget about species like us surviving - unless you've got 100 years worth of food stored underground enough for a small community. We need to detect and deflect the next killer asteroid.

Sounds pretty severe.

The analysis clarified the sequence of events after the big impact. Immediately after the impact, certain areas of the ocean were devoid of oxygen and hostile to most algae, but close to the continent, microbial life was inhibited for only a relatively short period: in probably less than 100 years, algal productivity showed the first signs of recovery. In the open ocean, however, this recovery took much longer: previous studies have estimated that the global ocean ecosystem did not return to its former state until 1 to 3 million years following the impact.

Rather than spend money on another trip to the Moon or Mars we ought to take the same money and put it toward defense against space threats. Ditto for other extinction threats. My motto: First, don't die.

By Randall Parker    2009 October 04 11:05 PM   Entry Permalink | Comments (7)
2009 January 02 Friday
More Evidence For Asteroid Clovis Extinction

A mere 12,900 years ago Clovis civilization in North America got brought down by an asteroid.

Abundant tiny particles of diamond dust exist in sediments dating to 12,900 years ago at six North American sites, adding strong evidence for Earth's impact with a rare swarm of carbon-and-water-rich comets or carbonaceous chondrites, reports a nine-member scientific team.

These nanodiamonds, which are produced under high-temperature, high-pressure conditions created by cosmic impacts and have been found in meteorites, are concentrated in similarly aged sediments at Murray Springs, Ariz., Bull Creek, Okla., Gainey, Mich., and Topper, S.C., as well as Lake Hind, Manitoba, and Chobot, Alberta, in Canada. Nanodiamonds can be produced on Earth, but only through high-explosive detonations or chemical vaporization.

Last year a 26-member team from 16 institutions proposed that a cosmic impact event, possibly by multiple airbursts of comets, set off a 1,300-year-long cold spell known as the Younger Dryas, fragmented the prehistoric Clovis culture and led to the extinction of a large range of animals, including mammoths, across North America. The team's paper was published in the Oct. 9, 2007, issue of the Proceedings of the National Academy of Sciences. (News release on the 2007 paper is available at: http://tinyurl.com/82988t, with link to a copy of that paper.)

We really should develop a much bigger asteroid detection and tracking system and an asteroid defense system. Really, I'm serious. This is more important than the manned space program and more important than probes that go to other planets. Heck, there's even a scientific angle because knowing a lot more about asteroids will provide insights into the solar system's development and even identify asteroids useful for terraforming Mars.

By Randall Parker    2009 January 02 10:20 PM   Entry Permalink | Comments (11)
2008 July 01 Tuesday
Canadian Satellite To Search For Asteroids

Asteroids are like cancer. Early detection is the key to effective treatment. An asteroid wiped out the dinosaurs. A big enough asteroid could wipe out humanity if we do not find it years before it strikes Earth. Therefore a cheap Canadian space telescope satellite designed to search for asteroids is a really good idea.

Canada is building the world’s first space telescope designed to detect and track asteroids as well as satellites. Called NEOSSat (Near Earth Object Surveillance Satellite), this spacecraft will provide a significant improvement in surveillance of asteroids that pose a collision hazard with Earth and innovative technologies for tracking satellites in orbit high above our planet. Weighing in at a mere 65-kilograms, this dual-use $12-million mission builds upon Canada’s expertise in compact “microsatellite” design. NEOSSat will be the size of a large suitcase, and is cost-effective because of its small size and ability to “piggyback” on the launch of other spacecraft. The mission is funded by Defence Research Development Canada(DRDC) and the Canadian Space Agency(CSA). Together CSA and DRDC formed a Joint Project Office to manage the NEOSSat design, construction and launch phases. NEOSSat is expected to be launched into space in 2010. The two projects that will use NEOSSat are HEOSS (High Earth Orbit Space Surveillance) and the NESS (Near Earth Space Surveillance) asteroid search program.

But if the Canadians find an asteroid is going to wipe us out will they burrow under ground and not tell anyone else? More room for them, eh?

Although NEOSSat’s 15-centimetre telescope is smaller than most amateur astronomers’, its location approximately 700 kilometres above Earth’s atmosphere will give it a huge advantage in searching the blackness of space for faint signs of moving asteroids. Twisting and turning hundreds of times each day, orbiting from pole to pole every 50 minutes, and generating power from the Sun, NEOSSat will send dozens of images to the ground each time it passes over Canada. Due to the ultra-low sky background provided by the vacuum of space, NEOSSat will be able to detect asteroids delivering as few as 50 photons of light in a 100-second exposure.

We really ought to put up some more powerful satellites and find all the asteroids at a much faster rate. Why not remove this risk from our lives?

By Randall Parker    2008 July 01 04:52 PM   Entry Permalink | Comments (13)
2007 December 18 Tuesday
Tunguska Simulation Shows Higher Risk From Smaller Asteroids

Smaller asteroids are more dangerous than previously thought.

ALBUQUERQUE, N.M. — The stunning amount of forest devastation at Tunguska a century ago in Siberia may have been caused by an asteroid only a fraction as large as previously published estimates, Sandia National Laboratories supercomputer simulations suggest.

“The asteroid that caused the extensive damage was much smaller than we had thought,” says Sandia principal investigator Mark Boslough of the impact that occurred June 30, 1908. “That such a small object can do this kind of destruction suggests that smaller asteroids are something to consider. Their smaller size indicates such collisions are not as improbable as we had believed.”

Because smaller asteroids approach Earth statistically more frequently than larger ones, he says, “We should be making more efforts at detecting the smaller ones than we have till now.”

We need to search harder for the larger number of smaller asteroids. Our risk of death and destruction from asteroids is larger than previously believed.

The Tunguska blast has a downward direction that amplifies its destructive effect on the surface of the Earth.

Simulations show that the material of an incoming asteroid is compressed by the increasing resistance of Earth’s atmosphere. As it penetrates deeper, the more and more resistant atmospheric wall causes it to explode as an airburst that precipitates the downward flow of heated gas.

Because of the additional energy transported toward the surface by the fireball, what scientists had thought to be an explosion between 10 and 20 megatons was more likely only three to five megatons. The physical size of the asteroid, says Boslough, depends upon its speed and whether it is porous or nonporous, icy or waterless, and other material characteristics.

We should try much harder to identify the asteroids that are going to collide with the Earth in the future. The sooner we identify them the easier it will be to deflect them from their paths.

The Tunguska event felled over 80 million trees and is a topic of active research which has generated lots of cool photographs.

By Randall Parker    2007 December 18 10:42 PM   Entry Permalink | Comments (2)
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