Sunday, August 8, 2010

What's Up? The Einstein Revolution

Welcome back to What's Up?

When we look up at night we see the stars and planets above, rotating hour by hour and night by night, just like clockwork. It's easy to appreciate the night sky's beauty, but sometimes we forget those who have helped figure out how the universe ticks.

The most well known of those great thinkers is most likely Albert Einstein. Although best known for his equation, e = mc2, which led to the development of the atomic bomb, his work has greatly helped in the understanding of the mysterious and quirky universe we live in.
Albert Einstein showing off a few equations.

Before Einstein, Mercury's odd shifting orbit could not be explained. Einstein's Special Theory of Relativity explained Mercury's orbit and got rid of the need for "fudge factors" in the equations or a hidden planet near the sun.

Einstein applied his equations to the entire universe and found that any mass in the universe would have enough gravity to eventually cause the universe to collapse in on its self. Since most astronomers at the time thought the universe was unchanging, he added a "cosmological constant" that would push back against gravity to prevent the universe from collapsing.

Just over a decade after adding the cosmological constant, it was discovered that the universe was expanding and there was no need for a cosmological constant to keep it from collapsing. Einstein called this the biggest blunder of his career.

Ironically, in 1996, researchers discovered that the rate at which the universe is expanding is getting faster and faster, it is accelerating! There is now a need for something similar to a cosmological constant to account for the accelerating expansion. The force driving the acceleration is referred to as dark energy, and is one of the biggest areas of research in astronomy today.

Einstein also realized that light is composed of individual particles and that light can be affected by gravity.
Photons being bent around the Sun.

Four years after Einstein's General Theory of Relativity in 1915, astronomers observed stars near the Sun during a solar eclipse. With the Moon blocking the Sun, it was easy to see where nearby stars were. Some of these stars appeared to out of place.

The light from the stars had been bent by the gravity of the Sun! This observation confirmed General Relativity and made Einstein an instant scientific celebrity.

From the same theory he also predicted that if something travels near the speed of light, the object will shrink in length, become more massive, and time will slow down for that object. Being in a gravitational field can also cause time to slow down. These observations may seem extremely crazy, but they have been proven to be true.

Communications satellites need to have Einstein's equations programmed into them. They orbit hundreds of kilometers above us and they don't feel as much gravity as we do, down here on the surface of the Earth. Since we experience more gravity, our clocks run a bit slower than the satellites' clocks. 

Without Einstein's equations, the difference between our clocks and the satellites' clocks would add up. A simple GPS system would start to drift within minutes without his equations. 

The next time you pick up your cell phone or turn on your GPS system in your car, remember that Einstein's equations are running inside the device.

Although quite comprehensive, Einstein's theories of Special and General Relativity can't explain the beginning of the universe, how gravity works on small scales, or what it is like inside a black hole.

Until those mysteries are solved, let's see what's up in this month's sky.

The new Moon will be on August 10, which allows for a perfect sky on August 12, the best night for watching the Perseid meteor shower. Rates can get up to around 100 per hour but the usual rate is around 60 per hour, or one every minute. 

To watch the meteor shower, find something to lie on, dress very warm, and look up sometime after sunset. The shower should get better as the night progresses.

The full Moon will be on August 24, and will be the smallest full Moon of the year.

The Athena Community Astronomy Club will have its monthly meeting at the Wilmot Community Centre from 7pm to 9pm on Sunday, August 29. Guests are always welcome.

The club will be continue its weekly boardwalk viewing sessions every clear Wednesday this month along the Summerside baywalk, by the Shipyard Market building, shortly after sunset.

Until next month, just look up!

Hey Kids...
If you have ever asked anyone whether airplanes can fly in space, you likely were told that they can't because there is no air in space. They are only partly right. There is a new plane called VSS Enterprise which is actually two planes joined together with a rocket underneath them. It's not going to be cheap at first but maybe someday you'll take a ride in this futuristic space plane.
VSS Enterprise in flight.

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