What would happen if I drilled a tunnel through the center of the Earth and jumped into it?

Although it would be impossible to do this on earth, you actually could do this on the moon. The moon has a cold core and it also doesn’t have any oceans or groundwater to mess things up. In addition, the moon has no atmosphere, so the tunnel would have a nice vacuum in it that eliminates aerodynamic drag.

So, imagine that the tunnel through the moon is 20 feet (7 meters) in diameter. Down one side is a ladder. If you were to climb down the ladder, what you would find is that your weight decreases. Gravity is caused by objects attracting one another with their mass (see Question 232). As you descend into the tunnel, more and more of the moon’s mass is above you, so it attracts you upward. Once you climbed down to the center of the moon you would be weightless. The mass of the moon is all around you and attracting you equally, so it all cancels out and you would feel weightless.

If you were to actually leap into the tunnel and allow yourself to fall, you would accelerate toward the center to a very high speed. Then you would zoom through the center and start decelerating. You would eventually stop when you reached the tunnel’s lip on the other side of the moon, and then you would start falling back down the tunnel in the other direction. You would oscillate back and forth like this forever.

If you could do this on earth, one amazing effect would be the ease of travel. The diameter of the earth is about 12,700 kilometers (7,800 miles). If you drilled the tunnel straight through the center and could create a vacuum inside, anything you dropped into the tunnel would reach the other side of the planet in just 42 minutes!

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originally published on Howstuffworks.com

The threat of Space Debris

Yesterday marked a momentous day in U.S. history as NASA launched its final space shuttle, ending a 30-year era. Four astronauts—commander Chris Ferguson, pilot Doug Hurley and mission specialists Rex Walheim and Sandy Magnus—are leading the 12-day Atlantis mission, the 135th and final flight of the storied space shuttle program. After Atlantis returns to Earth, NASA will officially retire the program and shift its focus to developing next-generation crew exploration vehicles (CEV) capable of carrying crew and cargoes to Earth’s orbit, the moon and Mars.

But just days before the Atlantis launch, something unexpected made headlines.

Rocketing past the International Space Station at 29,000 miles per hour, a piece of space debris came only 1,100 feet away from a collision, forcing crew members to take refuge in two space capsules reserved for an emergency escape.

Read the rest of this article @ Techcrunch.com

Earthquake shifted balance of Earth / Japan

Last week’s devastating earthquake and tsunami in Japan has actually moved the island closer to the United States and shifted the planet’s axis.

The quake caused a rift 15 miles below the sea floor that stretched 186 miles long and 93 miles wide, according to the AP. The areas closest to the epicenter of the quake jumped a full 13 feet closer to the United States, geophysicist Ross Stein at the United States Geological Survey told The New York Times.

 

The world’s fifth-largest, 8.9 magnitude quake was caused when the Pacific tectonic plate dove under the North American plate, which shifted Eastern Japan towards North America by about 13 feet (see NASA’s before and after photos at right). The quake also shifted the earth’s axis by 6.5 inches, shortened the day by 1.6 microseconds, and sank Japan downward by about two feet. As Japan’s eastern coastline sunk, the tsunami’s waves rolled in.

Why did the quake shorten the day?  The earth’s mass shifted towards the center, spurring the planet to spin a bit faster. Last year’s massive 8.8 magnitude earthquake in Chile also shortened the day, but by an even smaller fraction of a second. The 2004 Sumatra quake knocked a whopping 6.8 micro-seconds off the day.