APOD: 2025 April 23 Б An Almost Everything Sky
23.04.2025

This surprising sky has almost everything. First, slanting down from the upper left and far in the distance is the central band of our Milky Way Galaxy. More modestly, slanting down from the upper right and high in Earth's atmosphere is a bright meteor.

Comet LINEAR: Fade To Black
13.09.2000

Only last month the stage was set for Comet LINEAR (C/1999S4 LINEAR) to become the first "naked-eye" comet of Y2K. It didn't fill that role, of course, but it did turn in a very dramatic performance.

Europa: Oceans of Life?
6.08.1996

Is there life beneath Europa's frozen surface? Some believe the oceans found there of carbon-enriched water are the best chance for life, outside the Earth, in our Solar System. Europa, the fourth largest moon of Jupiter, was recently discovered to have a thin oxygen atmosphere by scientists using the Hubble Space Telescope.

Stars in the Infrared Sky
18.09.1996

What if you could see infrared light? Because this light is less absorbed by dust than visible light, you could peer into the center of our Milky Way Galaxy. The stars there are normally hidden from direct view by the interstellar dust clouds which line the Galactic plane.

Southern Neptune
29.05.1997

Neptune, the Solar System's outermost gas giant planet, is 30 times farther from the Sun than Earth. Twelve years after a 1977 launch, Voyager 2 flew by Neptune and found surprising activity on a planet that receives only 3 percent as much sunlight as Jupiter.

Comet Wild 2s Nucleus from Stardust
3.01.2004

What does a comet nucleus look like? Yesterday the robot spacecraft Stardust answered this question by returning the most detailed images yet of the center of a comet. The icy centers of comets are usually hidden from Earth-bound telescopes by opaque dust and gas that boils off during approach to the Sun.

Spitzer s Orion
18.08.2006

Few cosmic vistas excite the imagination like the Orion Nebula, an immense stellar nursery some 1,500 light-years away. Also known as M42, the nebula is visible to the unaided eye, but this stunning...

An X Class Flare Region on the Sun
6.11.2007

Why does the Sun flare? Unpredictably, our Sun unleashes tremendous flares expelling hot gas into the Solar System that can affect satellites, astronauts, and power grids on Earth. This close up of an active region on the Sun that produced a powerful X-class flare was captured by the orbiting TRACE satellite.

Comet 45P Returns
2.01.2017

An old comet has returned to the inner Solar System. Not only is Comet 45P/HondaMrkosPajduАkovА physically ancient, it was first discovered 13 orbits ago in 1948. Comet 45P spends most of its time out near the orbit of Jupiter and last neared the Sun in 2011.

Comet Hale-Bopp Outbound
10.09.1997

Hale-Bopp, the Comet of the Century, is leaving the inner Solar System. Outbound at about 12 miles per second it is presently nearing the main asteroid belt between Mars and Jupiter. This false-color image represents a recent view from low Earth orbit showing the comet surrounded by its shrinking coma against a background of stars.