Astronomer and author speaks on possible asteroid impacts

An asteroid causing an explosion with the power of thousands of tons of TNT is more likely than some people may think, and it could happen in this lifetime.

In fact, it’s the most likely threat against life on Earth as we know it, astronomer Philip Plait said.

In honor of Carl Sagan day, Plait, author of the new book, “Death from the Skies: These Are the Ways the World Will End,” gave a lecture Saturday at the Whittenberger Auditorium.

The talk was about the danger of asteroids on their way to Earth right now.

“The chance of impact is 100 percent if we don’t do anything about it,” Plait said.

A chunk of rock called the Chelyabinsk meteor destroyed parts of Russia this February. Although nobody was killed, Plait said the meteor was big enough to make scientists reassess how seriously asteroid impacts need to be taken.

Chelyabinsk was 19 meters in diameter, a small threat compared to some of the asteroids swirling around our solar system.

Plait said some are bigger than Mount Everest.

“When you think of something that big just floating out there around the sun, you don’t want it anywhere close to your planet,” he said. “You have to find a way to knock it out of the way, slow it down or speed it up so it misses Earth.”

It’s a task that costs hundreds of millions of dollars at least, he said.

Senior scientist for NASA David Morrison visited campus in October and also spoke on the possibility of asteroids striking Earth. He said with enough warning scientists can change the orbit of an asteroid to keep it from making contact.

Plait said when scientists and satellites discover a meteorite whose trajectory crosses Earth, Congress has to give permission to send a pricey probe out to either blow it up or push it over.

And despite the millions of dollars of rockets and probes sent to do the job, it’s a lot harder than it seems.

Some asteroids are actually so large they have enough gravity to hold a moon in place.

Plait said blowing up an asteroid that big could result in it breaking into several pieces, and if it’s not done far enough away from Earth it will result in more widespread damage.

“It’s like a nuclear blast without the radiation,” Plait said. “It will kill everybody.”

Just last month Russian scientists spotted an asteroid that could be dangerously close to Earth by 2032.

It’s called 2013 TV135, and is 40 meters long.

It’s predicted to miss Earth by almost 2 million kilometers, but if calculations are off and it does end up hitting the planet it will explode with an estimated force equivalent to 2,500 megatons of TNT.

But Plait said there is a bright side.

“Asteroid impacts are the only natural disasters that are 100 percent preventable,” he said. “You just have to spend the money to do it.”

And he said that’s really what the end of the world revolves around.

“Pick your disaster,” he said. “It all depends on where you invest the dollars to prevent them.”

Follow reporter Ashley Jenkins on Twitter @ashley_morga.