Earth's Magnetic Field

It's a good thing Earth has a magnetic field! If it didn't, we'd be showered with solar radiation 24/7 and probably wouldn't survive for very long! But what is this magnetic field and how does it work? Astronomers have some idea…

The Earth's magnetic field is thought to be caused by a molten iron core deep inside Earth. With fancy math and physics one can prove that a molten electrically conductive material  that is spinning will produce a magnetic field. This magnetic field is very similar to the one a bar magnet produces, just on a much larger scale. A bar magnet always has a north and south pole. If you sprinkle some iron filings around a bar magnet, you will see that they align themselves in a curved pattern extending from the north to the south pole. The iron filings are tracing the magnetic field lines, or in other words the force, produced by the magnet. One would naturally think that the north pole on Earth should represent the north end of the "bar magnet" inside Earth, and the south pole the south end, but it's actually the exact opposite! Let's stop and think… opposite ends of a magnet attract, while similar ends repel. So if a compass always points North, it must be attracted to the southern magnetic pole! Another fun fact about our magnetic poles is that they do not coincide with the physical north and south poles on Earth, they actually move quite a bit each year! In 2005, the north pole was measured to be at about 83N 114W, but today it is further west by roughly 10 degrees! Astronomers and geologists don't fully understand the production of Earth's magnetic field, and therefore don't fully understand why it is moving, especially at such a quick pace. There's much more work to be done on this subject.

Apollo Moon Landings

I'm sure many of you remember that glorious day when man first stepped on the moon. The date was July 16, 1969, the mission: Apollo 11. Neil Armstrong, Buzz Aldrin, and Michael Collins left the Earth that day, and five days later made history by putting the mark of a human being on another astronomical body.  This is the day most people think of when someone mentions the moon landing, but we've actually sent man to the moon a total of 7 times. Missions Apollo 11 through Apollo 17 all rocketed towards the moon, and all but Apollo 13 landed successfully on the moon. During each mission astronauts set foot on the moon, and the Apollo 15 mission was the first to drive a vehicle on the moon, called the lunar rover (pictured above). After Apollo 17, manned missions to the moon were canceled due to lack of funding. NASA needed to make some budget cuts, and decided to put money towards Skylab instead. Man has not set foot on the moon since. Many orbiters and robotic landers have studied the moon since then, and the next mission, a set of orbiters called GRAIL, is set to launch from Cape Canaveral on September 8th, 2011.

The movie Apollo 18 comes out this Friday and it looks like it's going to be a great sci-fi thriller! It's based on the idea that NASA actually did send astronauts to the moon again as an Apollo 18 mission, but never told the world because of what they found…. aliens on the moon! Of course these creatures are hostile and live on the dark side of the moon, what sci-fi movie would be complete without killer aliens? I'm surprised it took 40 years to come out with a film like this, and I hope it's a good one!

Image Credit: NASA