Hammer vs. feather on the Moon

Nothing like a little science on the Moon, I always say.

Astronaut David Scott in 1971, from the Apollo 15 Lunar Surface Journal. Scott was part of the Apollo 15 crew, and applied Galileo's findings about gravity and mass by testing a falcon feather and a hammer. The film, shown in countless high school physics classes, is the nerdy, oft-neglected cousin of Neil Armstrong's space paces.

That's no moon, it's a seamount

There's a fascinating tidbit in this Google blog post about the non-discovery of Atlantis in Google Earth. It concerns how the depth of the ocean floor is measured.

Now you're probably wondering where the rest of the depth data comes from if there are such big gaps from echosounding. We do our best to predict what the sea floor looks like based on what we can measure much more easily: the water surface. Above large underwater mountains (seamounts), the surface of the ocean is actually higher than in surrounding areas. These seamounts actually increase gravity in the area, which attracts more water and causes sea level to be slightly higher. The changes in water height are measurable using radar on satellites.

Wow! (via ben fry)

Satellites measuring the earth's gravity from orbit

Satellites measuring the earth's gravity from orbit detected a change in gravity from the massive earthquake that caused the tsunami in the Indian Ocean. "The gravity at the earth's surface decreased by as much as about 0.0000015 percent, meaning that a 150-pound person would experience a weight loss of about one-25,000th of an ounce."

Physicist Lawrence Krauss sums up his thoughts

Physicist Lawrence Krauss sums up his thoughts from a small conference he organized on the topic of gravity. "There appears to be energy of empty space that isn't zero! This flies in the face of all conventional wisdom in theoretical particle physics. It is the most profound shift in thinking, perhaps the most profound puzzle, in the latter half of the 20th century."

I can't tell if this is a

I can't tell if this is a joke or not, but someone seems to be quite skeptical about the "theory of gravity" on this Christian Forums site. "are you going to tell me that the gravity of the sun is strong enough to keep PLUTo in orbit but not an airplane or a little bird??????"

A moving mass has been shown to

A moving mass has been shown to generate a gravitomagnetic field (just like a moving electrical charge creates a magnetic field) and "the measured field is a surprising one hundred million trillion times larger than Einstein's General Relativity predicts". (via rw)

Lisa Randall and Raman Sundrum have proposed

Lisa Randall and Raman Sundrum have proposed some ideas about gravity, extra dimensionality, and string theory that may be testable when the Large Hadron Collider goes online at CERN in 2007.