Almost 400,000 years after the universe was created in the big bang, it cooled sufficiently for neutral atoms to form, thereby allowing the pervasive light to propagate almost completely ...

The Earth, Mercury, Venus, and Mars are known as the rocky planets because they are composed predominantly of rocks which contain silicon, iron, and other heavy elements. Jupiter and Satu...

The glowing nebula of warm gas and dust known as IC348 is located about 1,000 light-years from Earth, in the direction of the constellation of Perseus. It has long been known that IC 348...

There are many different kinds of stars, with the primary determining factors being a star's mass and age. The naked-eye star Phi Herculis (Phi Her), located near the left foot of the co...

Venus is so much like the Earth in its size and composition that it is sometimes called our sister planet, but it differs in at least one relatively dramatic way: it has very little water...

For a few hundred thousand years after the creation of the universe in the big bang, the universe was so hot that neutral atoms could not exist. Once the universe cooled to a few thousand...

Honolulu, HI Today, astronomers unveiled the sharpest photograph ever taken of the nearby spiral galaxy Messier 81. The image from NASA's Hubble Space Telescope shows stunning detail in ...

Cambridge, MA Astronomers are hunting an elusive target: rogue black holes that have been ejected from the centers of their home galaxies. Some doubted that the quarry could be spotted, ...

The star HD 189733 is located about sixty light-years from Earth. Two years ago a planet was discovered orbiting this star -- a so-called "hot Jupiter" planet, one whose mass is similar...

The Earth is not a perfectly round sphere, nor is its internal composition exactly homogeneous. As a result, the Earth's gravitational field varies from place to place -- a ball dropped ...