APOD: 2026 January 20 Б Io in True Color
20.01.2026

The strangest moon in the Solar System is bright yellow. The featured picture, an attempt to show how Io would appear in the "true colors" perceptible to the average human eye, was taken in 1999 July by the Galileo spacecraft that orbited Jupiter from 1995 to 2003.

Sun and Winter Solstice 1996
21.12.1996

Today is the Winter Solstice for 1996. After steadily sinking in Northern Hemisphere skies, the Sun is now at its lowest declination - marking the first day of Northern Winter (but Southern Summer!). The Earth...

M100 and the Expanding Universe
9.01.1996

The distance to the swirling grand design spiral M100 is causing quite a stir among astronomers. Many believe that the Hubble Space Telescope's recent distance measurement to this galaxy accurately calibrates the expansion rate of the universe. Others believe this distance measurement is misleading.

Tycho's Supernova Remnant in X-ray
23.06.1996

How often do stars explode? By looking at external galaxies, astronomers can guess that these events, known as a supernovae, should occur about once every 30 years in a typical spiral galaxy like our MilkyWay.

Cassini To Saturn
29.08.1997

Scheduled for launch in October, the Cassini spacecraft will spend seven years traveling through the Solar System -- its destination, Saturn. On arrival Cassini will begin an ambitious mission of exploration which will include parachuting a probe to the surface of Titan, Saturn's largest moon.

Hen 1357: New Born Nebula
3.04.1998

This Hubble Space Telescope picture shows Hen-1357, the youngest known planetary nebula. Graceful, gentle curves and symmetry suggest its popular name - The Stingray Nebula. Observations in the 1970s detected no nebular material, but this image from March 1996 clearly shows the Stingray's emerging bubbles and rings of shocked and ionized gas.

A Wind From The Sun
18.03.2000

A wind from the Sun blows through our Solar System. The behaviour of comet tails as they flapped and waved in this interplanetary breeze gave astronomers the first hint of its existence. Streaming outward at 250-400 miles/second, electrons and ions boiling off the Sun's incredibly hot

NEAR to Asteroid Eros
5.02.2000

On December 23, 1998 the Near Earth Asteroid Rendezvous (NEAR) spacecraft flew by asteroid 433 Eros. The robotic spacecraft was intended to brake and orbit Eros, but an unexpected shutdown of its main engine caused this plan to be aborted.

Aeolian Mars
2.02.2000

Mars' atmosphere is relatively thin, still when martian winds blow they weather and shape its surface. Like familiar aeolian features on Earth, this field of dunes within Mars' Rabe crater exhibits graceful undulating ridges which can shift as windblown material is deposited on the dunes' windward face and falls away down the steeper leeward slopes.

The Cat's Eye Nebula
31.10.1999

Three thousand light-years away, a dying star throws off shells of glowing gas. This image from the Hubble Space Telescope reveals The Cat's Eye Nebula to be one of the most complex planetary nebulae known.