NASA Administrator Michael D. Griffin met last week with reporters and editors at The Post. Here are some of the questions and answers:

What can humans learn in space that robots couldn't?

The thing that you can learn with humans in scientific enterprises are all of the things that you didn't send the robot to find out. With a human you're doing the opportunistic plan, the uncorrelated observation. You know, you see this over here and that over there, and you put them together.

When you know what question you want to ask and what measurement you want to make, it's almost always to your advantage to do that robotically or, at most, use the human to put the thing in place. There's no question about it. When you don't know what you don't know, when you don't know what the questions are, we do very poorly at attempting to figure out what those questions ought to be by using robots.

Giant tsunamis, super volcanoes and earthquakes could pose a greater threat than terrorism, scientists claim.

Global Geophysical Events, or "Gee Gee's", as they are nick-named, are not being taken seriously enough, they say.

The global community needs to monitor these risks, and develop strategies to cope in the face of a catastrophe.

However, we are making good progress in reducing the threat of asteroid impacts, the researchers said during a briefing at the Royal Institution, UK.

Battening down

Since 9/11 we have become acutely aware of the threat of terrorism. Governments worldwide are battening down the hatches and ratcheting up the security.

But, in terms of grave threats, are we really looking in the right direction?

Giant walls of water that can devastate coastal cities, volcanoes so big that their ash crushes houses 1,500km (932 miles) away, giant earthquakes and asteroid impacts. These are very rare events and, if we are lucky, nothing like them will happen in our lifetimes.

But in the longer term, Gee Gee's may be our undoing if we do not take action. According to researchers, careful preparation could potentially save thousands of lives.

Examining a Probabilistic Doomsday Argument
Commentary

Is the sky falling? And if so, when? Even when they're baseless, constant reports about nuclear weapons proliferation, pandemic diseases and environmental catastrophes revive these perennial human questions and contribute to a feeling of unease.

So too did the recent passing of an asteroid almost 100 feet in diameter within 30,000 miles of the Earth. Such news stories make a recent abstract philosophical argument a bit more real.

Developed by a number of people including Oxford philosopher Nick Bostrom and Princeton physicist J. Richard Gott, the Doomsday Argument (at least one version of it) goes roughly like this.

They are out there, ready to smack into the Earth and wipe out human civilization, but astronomers said on Wednesday they are well on their way to finding every asteroid that poses a threat.

The next task will be to look for smaller objects that might just destroy, say, a city, the experts told the U.S. Senate's Subcommittee on Science, Technology and Space.

In an update on the Near Earth Object Observation Program, experts told the Senate subcommittee that they are on schedule to finding everything bigger than 1 kilometer in diameter that might approach the planet.

"The survey officially started in 1998 and to date more than 700 objects of an estimated population of about 1,100 have been discovered, so the effort is now believed to be over 70 percent complete and well on the way to meeting its objective by 2008," NASA's Lindley Johnson told the hearing.

Next time an asteroid or comet is on a collision course with Earth you can go to a web site to find out if you have time to finish lunch or need to jump in the car and DRIVE.

University of Arizona scientists are launching an easy-to-use, web-based program that tells you how the collision will affect your spot on the globe by calculating several environmental consequences of its impact.

An exploding star may have destroyed part of Earth's protective ozone layer two million years ago, devastating some forms of ancient marine life, according to a new theory presented at this week's meeting of the American Astronomical Society.

The new theory brings together puzzling clues from several different fields of research, including paleontology, geology, and astronomy.

Narciso Benitez, an associate research scientist in astronomy at Johns Hopkins University, said the "missing smoking gun" that brought the clues together was the revelation that a stellar cluster with many large, short-lived stars prone to producing supernovae had passed near Earth's solar system several million years ago.

The hunt for space rocks on a collision course with Earth has so far been pretty much limited to the Northern Hemisphere. But last week astronomers took the search for Earth-threatening asteroids to southern skies.

Astronomers using a refurbished telescope at the Australian National University's Siding Spring Observatory discovered their first two near-Earth asteroids (NEAs) on March 29. NEAs are asteroids that pass near the Earth and may pose a threat of collision.

Trying to defend against self-replicating weapons of mass destruction.

Smallpox has killed a billion humans. That's more deaths than in all modern wars combined. Yet despite its virulence, smallpox typically kills only 30 percent of the population it infects. Naturally evolving pathogens keep enough victims around to kill again.

Engineered pathogens can be different - as recent work in Australia has terrifyingly demonstrated. By inserting a mail-order gene into mousepox, scientists increased the death rate in mice to 100 percent. Even after vaccination, the rate was 60 percent.

We don't know whether the mail-order gene would have the same effect with smallpox. But the very idea is an example of the fear that led Bill Joy to write his frightening piece "Why the Future Doesn't Need Us," published four years ago this month in Wired.

Scientists at Cardiff University, UK, believe they have discovered the cause of crop failures and summer frosts some 1,500 years ago – a comet colliding with Earth. The team has been studying evidence from tree rings, which suggests that the Earth underwent a series of very cold summers around 536-540 AD, indicating an effect rather like a nuclear winter.

The scientists in the School of Physics and Astronomy believe this was caused by a comet hitting the earth and exploding in the upper atmosphere. The debris from this giant explosion was such that it enveloped the earth in soot and ash, blocking out the sunlight and causing the very cold weather.

The predecessor of hypothesized nano superweapons was the "atom bomb,” which was hypothesized since 1900 and became a reality in 1945. How and why did the United States win the "atom bomb” race against Hitler’s Germany?

Critics say American 'double standard' will undermine efforts to curb nuclear arms.

Research on a new generation of precision atomic weapons by the Bush administration threatens to undermine international efforts to stop the spread of nuclear arms and to tarnish recent successes, according to diplomats and nonproliferation experts.

Impact cratering is now recognized as a major geological process on Earth. In particular, giant impacts had a fundamental influence on the geological and biological evolution of our planet with possible climatic effects. There are more than 160 confirmed impact craters on Earth, among which 17 are located in Africa, but it is estimated that only 10% of impact craters larger than 10km and younger than 100Ma are known.

The Sahara is a particularly favorable region to host young impact craters, but according to cratering rate estimates, most of them still remain to be discovered, hidden under dry sandy sediments. Only four confirmed impact craters are currently known in eastern Sahara.

"The unleased power of the atom has changed everything save our modes of thinking and thus we drift toward unparalleled catastrophe."
- Albert Einstein

As kids, my friends and I stumbled across the old piece of plywood while hiking. Such large junk was a familiar site -- these woods on Chicago's South Side near Palos Forest Preserve were really not woods at all, but overgrown underbrush along the industrial Illinois & Michigan canal corridor. The piece of plywood was almost overlooked, but I noticed that if you jumped on it there was a bit of a bounce. We cleared off the dirt and grass. There were hinges; it was a makeshift door. With some effort we opened it and within seconds we pledged to keep our discovery secret. After all, it's not every day that you find buried in the woods a nuclear fallout shelter!

For the next few years, during the early '80s, my friends and I prepared for the end of the world. It wasn't enough to just plan -- the door we discovered became our escape hatch from the world, where we would adventure in role playing games like Twilight 2000 and Advanced Dungeons & Dragons. We didn't just believe the end was coming, we fantasized about it. Jimmy Carter reinforced our beliefs in his farewell address, Ronald Reagan said Star Wars could save some of us from an all-out attack, abc's The Day After prepared us for survival. Then the 1984 movie Red Dawn brought our past few years of post-apocalyptic planning to life on the silver screen. The apocalypse better get here soon, our kid-sized notions told us, otherwise we're all going to have to get jobs at McDonalds or the mall.