APOD: 2023 February 21 Б Comet ZTF over Yosemite Falls
21.02.2023

They are both falling. The water in Yosemite Falls, California, USA, is falling toward the Earth. Comet ZTF is falling toward the Sun. This double cosmic cascade was captured late last month as fading Comet C/2022 E3 (ZTF) had just passed its closest to planet Earth. The orange star just over the falls is Kochab.

Io in True Color
30.03.2014

The strangest moon in the Solar System is bright yellow. This 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.

Too Close to a Black Hole
26.10.2014

What would you see if you went right up to a black hole? Featured is a computer generated image highlighting how strange things would look. The black hole has such strong gravity that light is noticeably bent towards it - causing some very unusual visual distortions.

A Black Hole Disrupts a Passing Star
24.03.2020

What happens to a star that goes near a black hole? If the star directly impacts a massive black hole, then the star falls in completely -- and everything vanishes. More likely, though, the star...

Gravitational Tractor
7.07.2012

How would you change the course of an Earth-threatening asteroid? One idea - a massive spacecraft that uses gravity as a towline - is illustrated in this dramatic artist's view of a gravitational tractor in action.

NGC 6357: The Lobster Nebula
26.12.2018

Why is the Lobster Nebula forming some of the most massive stars known? No one is yet sure. Cataloged as NGC 6357, the Lobster Nebula houses the open star cluster Pismis 24 near its center -- a home to unusually bright and massive stars.

A Galaxy Collision in NGC 6745
2.11.2000

Galaxies don't normally look like this. NGC 6745 actually shows the results of two galaxies that have been colliding for only hundreds of millions of years. Just off the above photograph to the lower right is the smaller galaxy, moving away.

The Early Universe
16.02.1996

What did our universe look like when it was young? To answer this, cosmologists run sophisticated computer programs tracking the locations of millions of particles. The above animated frame is the result of such a calculation and shows how our universe might have looked when it was just a fracton of its current age.

Mercury: A Cratered Inferno
2.01.1999

Mercury's surface looks similar to our Moon's. Each is heavily cratered and made of rock. Mercury's diameter is about 4800 km, while the Moon's is slightly less at about 3500 km (compared with about 12,700 km for the Earth). But Mercury is unique in many ways.

APOD: 2025 February 26 Б Einstein Ring Surrounds Nearby Galaxy Center
26.02.2025

Do you see the ring? If you look very closely at the center of the featured galaxy NGC 6505, a ring becomes evident. It is the gravity of NGC 6505, the nearby (z = 0.042)...