“Noise” from space may help reveal mass of near-Earth asteroids

April 4th, 2009 - 5:18 pm ICT by ANI  

Washington, April 4 (ANI): Planetary scientists are all set to turn “noise” from the data obtained by NASA/ESA LISA satellites’ mission into useful information about the mass of near-Earth asteroids.

LISA is on a mission to detect gravitational waves - a warping of the space/time continuum that scientists hope to see directly for the first time.

Slated for launch no earlier than 2018, LISA will include three satellites connected by laser beams. The distance between the satellites should change as a gravitational wave passes.

Einstein’s General Theory of Relativity predicts that gravitational waves from exploding stars or colliding black holes ripple across the universe, causing other bodies to wobble like driftwood in a motorboat’s wake.

In 2006, planetary scientists realized that Near Earth Asteroids (NEAs) also would make the spacecraft wobble as they passed nearby, creating a distinct signature in the data being collected.

Pasquale Tricarico, a scientist at the Tucson-based Planetary Science Institute, expanded on that work to predict the number of asteroid encounters LISA can expect and how those encounters can be used to determine the mass of passing asteroids.

According to Tricarico, LISA can expect to see one or two known near-Earth asteroids a year, and a total of around ten during the expected mission lifetime.

When an encounter with a known asteroid shows up in the data, scientists will already know its trajectory.

“So from the signal, we can indirectly measure the asteroid’s mass because that’s the only uncertainty in the equation,” Tricarico said.

“These mass measurements are important because we only know the mass of asteroids that have been visited by spacecraft or the mass of a few binary asteroids observed from Earth,” he added.

“We always wonder about the porosity, the density, and this will give us measurements from additional asteroids,” he explained.

If a known asteroid passes one of the satellites and doesn’t leave a signature, “that allows us to put an upper limit on the mass of that asteroid,” Tricarico added.

Tricarico also has predicted the number of potential encounters with smaller, unknown NEAs.

If LISA starts detecting five asteroids a year instead of two or three, this could modify theories concerning the distribution of sizes in the NEA population. (ANI)

Related Stories

Tags: , , , , , , , , , , , , , , , , , , ,

Posted in Health Science |