Sunday, June 6, 2010

Defending the Earth

Welcome back to What's Up?

In the news this past month, David Attenborough, a British biologist, claimed that the Earth is undergoing one of the fastest rates of extinction in our planet's entire history. Species around the world are dying off due to climate change, pollution, and habitat loss.

These problems are largely human created problems, but they can be solved. 

If there are so many urgent problems on Earth, why spend money on space exploration?

There is a long list of good reasons to explore space and protecting Earth is one of them. After all, the Earth is part of the universe and is very vulnerable.

Lurking in the solar system are rocky objects called asteroids and icy/rocky objects called comets. There are a lot of these objects and some have very strange orbits that can can put them on a collision course with Earth.

A brilliantmeteor as it "burns" up in
the upper atmosphere.
Some of these asteroids are only specks of dust or the size of pebbles, while others are the size of cities. Every day 10,000 tonnes of asteroids, most smaller than a golf ball, fall to Earth. When they enter the atmosphere they are now called meteors or "shooting stars" as they burn up on their way down.

When Earth passes through a large stream of these dust or pebble sized objects, a meteor shower occurs. Instead of grabbing an umbrella during one of these showers, grab a warm sweater, something dry to lay on, look up, and enjoy the show.

When really large asteroids come in they may make it to the ground. Others heat up and explode in the sky.
Site of the explosion in Siberia
shortly after (above) and one
hundred years later (above).

In 1954, Ann Hodges of Sylacauga, Alabama became the first person known to have been hit by a meteorite. While taking a nap, a 4 kilogram (9 pound) meteorite smashed through her roof, bounced off her radio, and landed on her hip. 

In 1908 a relatively small asteroid or comet, about 50 meters (150 feet) in diameter, exploded in the sky above Siberia. The explosion was 1000 times more powerful than the atomic bomb dropped on Hiroshima. Around 2,000 square kilometers of trees were levelled in all directions, an area larger than Washington, D.C.

While objects like the one that exploded over Siberia only happen every few hundred years, they are extremely dangerous. In the past even larger objects have impacted Earth.

What the dino killer may
have looked like.
One day, 65 million years ago, the dinosaurs were wiped out by an asteroid the size of Mount Everest. This kind of event is so rare that it has only happened a few times since life arose on our planet.

While it may seem impossible to prevent these impacts, scientists and groups like the Planetary Society, are working on ways to steer such asteroids away from Earth's path.

Some ideas include using a nuclear bomb to push an asteroid slightly off-course, attaching a rocket and slowly pushing the asteroid, or even using the gravity from a satellite to slowly tug on an asteroid over many years. While all require advance warning, they can keep these dangerous objects away.

The only way to get advance warning is to keep an eye on the skies.

While we're watching the skies let's see what's up this month.

There will be a new moon on June 12 and a full moon on June 26.

The longest day of the year, the Summer Solstice, otherwise known as the first day of Summer, will be on June 21 this year.

Venus, Mars, and Saturn will be visible low in the west or southwest throughout the month. Venus will be the brightest, very low in the sky. Mars will be slightly higher and will appear as a red-orange "star." Saturn will be a little higher still and to the west a bit. It will be a dim yellow.

The Athena Community Astronomy Club will have its monthly meeting on the last Sunday of the month, June 27. The meeting is at the Wilmot Community Centre and runs from 7pm to 9pm. Guests are always welcome.

The club will also be having viewing sessions, every clear Wednesday evening, along the baywalk by the Shipyard Market building at dusk.

Until next month, just look up!

Hey Kids...
The United States launched a super-secret mini space shuttle last month. Nobody knows how long it will stay in space or even what it is doing up there. But now, a few backyard star gazers have found it and are tracking it. So much for being super-secret. With regular backyard telescopes, some people are even taking pictures of it. It is sometimes bright enough to be seen drifting across the sky as a faint dot in the night sky. You never know what you may see if you just look up!

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