The gravitational effect of the 50-50 nation is holding the poll numbers near parity.

ECONOMIST: How well did John Kerry do?

Such disturbance has traditionally been ascribed to the combined gravitational effect of all the stars of the earth's home galaxy, the Milky Way.

ECONOMIST: X marks the spot

Marcy and a team that includes Paul Butler of the Anglo-Australian Observatory are using the telescope to scan more than 400 stars for the characteristic "wobble" caused by the gravitational effect of planets on stars.

CNN: Astronomers spy new neighbors outside solar system

"The gravitational effect of the decapitation of the regime in Baghdad 24 hours ago has rippled right up here to the north, as was the hope and the expectation of allied coalition commanders, " Sadler said.

CNN: U.S. reinforcements arrive in Kirkuk

It could also cast light on the mystery of dark matter, a substance that pervades the universe in vastly larger quantities than familiar, visible matter, but whose existence can be inferred only by watching its gravitational effect on visible matter.

ECONOMIST: Particle accelerators

Perhaps its greatest moment came in 1979 when it was the first telescope to observe a gravitational lens, an effect where a "massive" object bends electromagnetic radiation such as light around it.

BBC: Aye to the telescope

The gravitational field around Mars would have a slingshot effect on a spacecraft, hurling it back toward earth with additional velocity.

WSJ: First Space Tourist to Outline Trip to Mars

The images from the Hubble, which has a clear view of the cosmos from its orbit above the Earth's turbulent atmosphere, will enable astronomers to gain a better understanding of black holes and the effect they have on material captured in their gravitational trap.

BBC: Hubble spies black hole gobbling galaxy

This corresponds to a place where the gravitational pulls of Mars and Jupiter have conspired to change the orbits of any asteroids much faster than the Yarkovsky effect could manage alone.

ECONOMIST: Asteroid impacts