June 21, 2018
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Asteroid to give Earth a close shave, and USM expert is looking forward to it

By Seth Koenig, BDN Staff

PORTLAND, Maine — At around 1:30 p.m. next Friday, Earth will have its closest brush in modern times with an asteroid, a prospect that excites University of Southern Maine assistant physics professor Julie Ziffer.

Ziffer, who was part of a team that in 2010 first discovered frozen water on the surface of an asteroid, said getting buzzed by one of the giant chunks of space rock provides scientists their best opportunity learn more about them. Today’s hottest topics for star gazers and aspiring space explorers come right out of science fiction, Ziffer said, with asteroids being sought as potential sites for mining precious metals or refilling passing spaceships with drinking water.

The asteroid named 2012 DA14 will come within 17,500 miles of Earth when it whips by on Feb. 15, which is closer to the planet than our weather satellites, she said.

“It’s the first in modern times that’s as large as it is and coming as close as it is,” Ziffer told the BDN Friday. “It’s large enough that if it were to impact us, it would be more powerful than the bombs dropped on Hiroshima and Nagasaki [during World War II] — it would cause large-scale devastation.

“In astronomical terms, it’s a very, very close call,” she continued. “We joke that we’ll be able to feel the breeze as it goes by.”

Mainers on Friday won’t feel any cosmic breeze, nor will they see the projectile, Ziffer said. The asteroid will pass most directly by Antarctica, she said, and even if it were flying across the Northern Hemisphere’s sky, it would be obscured by the afternoon daylight at the time it’s projected to pass.

Ziffer will deliver a lecture on asteroids at the university’s Southworth Planetarium in Portland on Thursday at 7 p.m. in recognition of the following day’s close encounter.

While Ziffer said there’s no chance 2012 DA14 will collide with Earth, there is a great chance that scientists here will be able to take close-up pictures of the space rock and continue collecting data about that object and others like it.

Asteroids — rich with metals such as iron, gold, cobalt and platinum — in recent years have become of great interest as potential mining sites, she said. Last month, a group of entrepreneurs and scientists announced the formation of the private firm Deep Space Industries, with a stated goal of asteroid mining.

That follows on the heels of Planetary Resources Inc., another private company with similar intentions formed in 2010 with the financial backing of Google co-founder Larry Page and big-budget Hollywood producer James Cameron.

“There will be the same types of metals on asteroids as there are on Earth. How abundant they are, we’re not sure,” Ziffer said. “That’s one of the reasons why, whenever we have an opportunity where one’s coming close, we try to get a better idea of what the composition is.”

Another way asteroids may be of use to humans could be for their water, the USM expert said. As mankind begins to set its eyes on more and more distant space travel, scientists will have to look for ways to sustain life without bringing resources from the home planet, she said.

“It would be very expensive to bring water [into space] from Earth,” Ziffer said. “Water is very heavy, and it’s difficult to get into space. It would be much easier to use asteroids kind of like gas stations.”

Asteroids have collided with Earth in the past. Ziffer said a massive crater near the Yucatan Peninsula off southeastern Mexico was caused by an asteroid strike about the time when the last dinosaurs went extinct.

“That crater is more than 100 miles wide, and so the thought is it would have created a sort of nuclear winter, with fires breaking out everywhere, ash covering the earth and the sun being blocked out,” she said. “There’s disagreement about whether it directly caused the dinosaur extinction event about 65 million years ago, but people are reasonably confident that an asteroid did strike the planet at that time.”

Another asteroid, about the size of the one passing by Earth next week, hit what is now Arizona about 50,000 years ago, Ziffer said, and one is believed to have smashed into Russia’s densely forested Siberia region as recently as 1908. The latter collision is known as the Tunguska event, based on the place in Siberia where it transpired.

“The explosion was big enough that there were reports as far away as England of the night sky lighting up,” she said.

Ziffer said another asteroid will be lined up for an impact with Earth someday — “It’s not a matter of if, but when,” she said — but humans can now track the objects with such precision that any threat could likely be “diverted” off its course well in advance of any collision. Researchers believe that asteroids could be rerouted with a simple “nudge” by rockets, she said.

But such steps won’t be necessary on Friday, when 2012 DA14 comes cheek-to-cheek with the planet, however. Ziffer said it will be a moment for study and awe, not panic.

“It’s coming close enough that we’re going to be able to take great pictures,” she said.

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