Tag Archives: physics

Back at work after 36 years

Lost Rover Found on Moon With Retroreflector Still Intact.

The rediscovery of the reflector could have an important impact in several areas of science that depend on accurately measuring the position and orbit of the Moon. Laser rangefinding currently provides the most precise tests of many aspects of gravity, including the strong equivalence principle, the constancy of Newton’s constant, geodetic precession, gravitomagnetism and the inverse square law.

Technical details at Laser Ranging to the Lost Lunokhod~1 Reflector.

A Laser Strike at the Galactic Center

Great picture at APOD

Why are these people shooting a powerful laser into the center of our Galaxy?

Phil Plait explains:

The laser shoots up into the sky and excites atoms in the upper atmosphere, causing them to glow. That makes an artificial and very bright star in the sky! The telescope can then use that star to track the distortions in the atmosphere and compensate for them, allowing the images it makes to be incredibly clear and sharp.

With the laser, modern computers, and adaptive optics astronomers have solved a problem with Earth-based optical telescopes that goes back to Galileo.

Note that this is a technique for visible light observations. Space-based observatories are needed for the parts of the electromagnetic spectrum that are blocked by the Earth’s atmosphere.

Joss Whedon teaches Physics

mia_mcdavid has been introducing our foster daughter, carpe_noctum_93, to the wonders of Joss Whedon’s creation, going through our complete DVD collections of both Buffy and Angel. Back in July I heard Jennifer Ouellette speak at Convergence, and decided it was time to read her book, The Physics of the Buffyverse.

Behind the fantastic properties of the vampires, demons, etc., there is actually a lot of good physics in the series. From electricity and the mechanics of martial arts to the Many World Interpretation of quantum mechanics, the writers of the series drew upon wide variety of concepts in physics. Ouellette neatly disentangles the real science from the fantastic elements, maintaining a witty style quite appropriate for the subject matter. It is absolutely non-technical—no math needed (Though that reminds me that I want to read her latest book).