Astronomy Picture Of the Day (APOD)The Belt of Venus
Although you've surely seen it, you might not have noticed it. During a cloudless twilight, just before sunrise or after sunset, part of the atmosphere above the horizon appears slightly off-color, slightly pink.
Spiral Galaxies in Collision
Billions of years from now, only one of these two galaxies will remain. Until then, spiral galaxies NGC 2207 and IC 2163 will slowly pull each other apart, creating tides of matter, sheets of shocked gas, lanes of dark dust, bursts of star formation, and streams of cast-away stars.
Our Moon's appearance changes nightly. This slow-loading time-lapse sequence shows what our Moon looks like during a lunation, a complete lunar cycle. As the Moon orbits the Earth, the half illuminated by the Sun first becomes increasingly visible, then decreasingly visible. The Moon always keeps the same face toward the Earth.
The Heart Of NGC 4261
Who knows what evil lurks in the hearts of galaxies? The Hubble knows. This Hubble Space Telescope picture of the center of the nearby elliptical galaxy NGC 4261 tells one dramatic tale. The gas and dust in this disk are swirling into what is almost certainly a massive black hole.
X ray Transit of Mercury
This sequence of false color X-ray images captures a rare event - the passage or transit of planet Mercury in front of the Sun. Mercury's small disk is silhouetted against the bright background of X-rays from the hot Solar Corona.
Shadow Of Phobos
Hurtling through space above the Red Planet, potato-shaped Phobos completes an orbit of Mars in less than eight hours. In fact, since its orbital period is shorter than the planet's rotation period, Mars-based...
Gamma Ray Bursting
Using graphics and data from NASA's Compton Gamma Ray Observatory, this animation illustrates one of the most exciting mysteries of modern astrophysics, gamma-ray bursts. Incredibly gamma-ray bursts, sudden flashes of radiation with over 100,000 times the energy of visible light photons, occur several times a day.
M32: Blue Stars in an Elliptical Galaxy
Elliptical galaxies are known for their old, red stars. But is this old elliptical up to new tricks? In recent years, the centers of elliptical galaxies have been found to emit unexpectedly high amounts of blue and ultraviolet light.
Aurora Through a Moonlit Sky
A night sky can glow in fascinating ways. Through a clearing in the woods, the pictured sky above Alaska shines by reflected light from a nearby city, by the brightness of the Moon, and by aurora.
The Rotten Egg Planetary Nebula
Not all evolving stars eject gas clouds that look like people. OH231.8+4.2 was a star much like our Sun that ran out of nuclear fuel to fuse in its core.