© Unknown
The Global Catastrophic Risks conference started yesterday morning and death by asteroids, comets and gamma ray bursts was on the agenda as experts discussed the statistical likelihood of these types of global catastrophes.

First up at the conference on Global Catastrophic Risks was the topic of asteroids, with David Morrison who is a NASA senior scientist. He spoke about the threat of a catastrophic asteroid strike and the Spaceguard Survey.

It is NASA's responsibility since 1998, to monitor the skies and detect near Earth asteroids that are larger than 1 kilometer in size, which is the size that, if it hit Earth, could end civilization.

Morrison stated that 80 percent of the near Earth asteroids that are 1 kilometer or larger have been identified and that he could assure those gathered at the conference that "We are not going the way of the dinosaurs." He also says the Spaceguard Survey has not turned up any near Earth asteroids as large as the one that is believed to have wiped out the dinosaurs.
Morrison pointed out that asteroid strikes are the only natural hazard that in principle can be completely eliminated. Thanks to the Spaceguard Survey, humanity will likely have decades of warning before an impending collision. Once alerted, missiles could be used to nudge a threatening asteroid so that it misses the earth.

Comment: Hmm...interesting to notice NASA senior scientist's (clearly unwarranted) optimism, when director of the public information resource Spaceguard UK says the following:

The experts are not remotely agreed on how worried we should be. Telescopes and satellites are now in a position to detect potential "planet-killers" - asteroids or comets over one kilometre in diameter - many years or even decades before they might collide with the Earth.

The problem, according to Jay Tate, director of the public information resource Spaceguard UK, is that no measures are in place to avert them, and smaller objects could still "whistle through" to strike us at any time. "Do you want to know how much warning we would have of a country or city-killing asteroid?" asks Tate. "About four seconds. A major impact is just as likely to happen before the end of this conversation as 10,000 years from now."

Then again, they are keeping their eye on the 210-330 meter asteroid Apophis, to which they say there is a 1 in 45,000 chance that it could hit the earth on April 13, 2036 and the next three or four years will allow them to specify the likelihood a little better.

Next up was Arnon Dar who is a Technion physicist, discussing Gamma Ray Bursts (GRBs).

© Wikimedia Commons
Asteroid (253) Mathilde taken up by the space probe NEAR on 27 June 1997 from a distance of 2400 km.
Gamma-ray bursts (GRB) are sudden, intense flashes of gamma-rays which, for a few blinding seconds, light up in an otherwise fairly dark gamma-ray sky. They are detected at the rate of about once a day, and while they are on, they outshine every other gamma-ray source in the sky, including the sun. GRBs are produced when a gigantic star goes supernova.

Dar highlights the Eta Carinae, which is 7,500 light years away and points out that it has been unstable, it is 100 times more massive than the sun and 5 million times brighter and then he gives the good news that it's axis is pointed away from the earth.

Lest everyone let their concern dwindle though, Anders Sandberg from the Future of Humanity Institute, states that "some astronomers are worried that we may be looking down the barrel of gamma ray gun when the WR 104 binary located 8,000 light years away goes supernova."

Next on the agenda for the conference was the topic of comets.

William Napier from the Center for Astrobiology at Cardiff University in Wales spoke on the topic of comets and he states that long-period comets, which are those coming from the Oort cloud and the Kuiper belt have very different properties and behave differently, and are thought to "constitute around 1 percent of the risk of catastrophic collision."

© Wikimedia Commons
Drawing of a massive star collapsing to form a black hole. Energy released as jets along the axis of rotation forms a gamma ray burst that lasts from a few milliseconds to minutes. Such an event within several thousand light years of Earth could disrupt the biosphere by wiping out half of the ozone layer, creating nitrogen dioxide and potentially cause a mass extinction.
Napier believes that is underestimating the threat because of Dark Comets, which are comets that do not have bright tails and therefore are harder to detect and he uses the IRAS-Araki-Alcock comet as an example, stating that it was detected "only two weeks before it came within 0.03 astronomical units of the earth (about 230 earth diameters) back in 1983-the closest of any known comet since 1770."
Napier argues that the record of large impact craters suggests that the earth experiences periods of cometary bombardment every 36 million years or so. He attributes the episodes to the sun's periodic passage through galactic plane where contact with molecular clouds dislodges comets from the Oort cloud surrounding the solar system. He believes that the earth is currently in a bombardment episode. "We have comet problem because they are hard to detect which means that we would have months or weeks of warning at most," said Napier.
The topics to be discussed next at the Global Catastrophic Risks conference in Oxford will be pandemics and nuclear war.

From all accounts it seems that for now, human beings are not in imminent danger from outer space.

Comment: Oh, really?!

Then again, outer space is not the only thing these scientists and experts are looking into.

On the last day of the conference, they are expected to discuss the unintended consequences of new technology, with one example being superintelligent machines that, if handled wrong, might cause the demise of Homo sapiens.

According the director of Oxford's Future of Humanity Institute, which is hosting the conference, Dr. Nick Bostrom, "Any entity which is radically smarter than human beings would also be very powerful. If we get something wrong, you could imagine the consequences would involve the extinction of the human species."

Comet P/Halley as taken March 8, 1986 by W. Liller, Easter Island, part of the International Halley Watch (IHW) Large Scale Phenomena Network.
Another topic being discussed by the CNN article linked above is how some experts believe that in as little as two decades "humans will become more non-biological than biological, capable of uploading our minds onto the Internet, living in various virtual worlds and even avoiding aging and evading death," according to Dr. Ray Kurzweil, who is an inventor and futurist who calculates technology trends using what he calls the law of accelerating returns, a mathematical concept that measures the exponential growth of technological evolution.

Sound like a science fiction movie?
In the 1980s, Kurzweil predicted that a tiny handheld device would be invented early in the 21st century, allowing blind people to read documents from anywhere at anytime; this year, such a device was publicly unveiled. He also anticipated the explosive growth of the Internet in the 1990s.
Other experts agree that humans will merge with machines before the end of this century, according to the CNN article.