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“The Tunguska event just 100 years ago reminds us that the threat of an asteroid strike is real,” said Ray Williamson, Executive Director of the Secure World Foundation (SWF). “If that object had struck in New York City or London, it would have killed hundreds of thousands and created untold fear in human hearts. Yet, as near Earth object strikes go, it was relatively small,” he pointed out.

“We need to be much better prepared than we are today to deal with this important, if uncommon, threat by creating the international institutions and governance methods to find objects likely to strike Earth and devise the means to divert them from Earth’s path,” Williamson explained.

Action agenda

Thwarting the threat of Earth-colliding asteroids – is on the action agenda list for former Apollo astronaut, Russell L. (Rusty) Schweickart.

While a civilization-smashing impact from a space object is a low probability, it is not zero…and there are other trouble-makers out there too. They are the smaller asteroids, in far greater number and could wreak havoc on our world, but in a more localized way.

Speaking recently at a Secure World Foundation luncheon at the University of Colorado – Boulder, Schweickart emphasized that what is needed is an international protocol – “mission rules” — that deal with asteroids that are menacing to Earth. Such a plan could calls upon nations around the globe to consider and embrace steps that can help mitigate the destructive nature stemming from an asteroid striking our planet.

Tree of life

Schweickart’s talk drew from his chairman position of the Association of Space Explorers’ Committee on Near Earth Objects and as Chairman of the B612 Foundation, dedicated to detecting, tracking and deflecting near Earth objects (NEOs).

Coming to grips with the NEO challenge, Schweickart emphasized, is more a matter of humanity’s readiness not to be dinosaurs – thought by many scientists to have been the victims of a huge asteroid impact some 65 million years ago. And that’s why we on Earth, he added, are faced with a key question: “To be…or not to be?”

Indeed, over billions of years, the Tree of Life here on Earth has been whacked time and time again by what Schweickart labeled as “the crazy cosmic gardener.”

“The good news is that we can do something about this,” the former astronaut explained. “The marriage of we human beings and the machines that we’ve created are now at a level of capability which enables us to fire the crazy cosmic gardener. We can stop this process from occurring again.”

Now, a research team led by Brown University planetary geologist James Head has determined that volcanism played a central role in forming Mercury’s surface. In a paper that appears in the July 4 issue of Science, part of a special section describing the MESSENGER spacecraft’s first flyby of Mercury, the researchers have found evidence of past volcanic  activity, suggesting that the planet underwent an intense bout of changes to its landscape about 3 to 4 billion years ago – and that the source for much of that reshaping was within.

“What this shows is that Mercury was not dead on arrival,” says Head, the paper’s lead author. “It had a pulse for a while. Now, we want to know when it had that pulse and what caused it to slow down and eventually stop.”

A major clue to Mercury’s geologic past came from the scientists’ finding of volcanic vents along the margins of the Caloris basin, one of the solar system’s largest and youngest impact basins. The group zeroed in on a kidney-shaped depression that was surrounded by a bright ring, lending a halo-like impression to the landscape. The scientists determined that the depression was a volcanic vent, and the bright ring around it was pyroclastic, remnants of lava that had been spewed outward, much like a volcanic fountain on Earth.

Another larger ring surrounding the vent and halo ring showed that another type of volcanism, called effusion, in which molten rock from within the planet oozes outward and covers the surface, had occurred. Together these deposits create a surface feature shaped like a volcanic shield – a clear sign to scientists that volcanic activity helped form the surrounding plains.