APOD: 2024 January 30 Б SLIM Lands on the Moon
30.01.2024

New landers are on the Moon. Nearly two weeks ago, Japan's Smart Lander for Investigating Moon (SLIM) released two rovers as it descended, before its main lander touched down itself. The larger...

Sun Halo at Winter Solstice
14.01.2002

Sometimes it looks like the Sun is being viewed through a large lens. In the above case, however, there are actually millions of lenses: ice crystals. As water freezes in the upper atmosphere, small, flat, six-sided, ice crystals might be formed.

Bright Lights, Dark City
18.08.2003

Last Thursday, millions of people had an unexpectedly good view of a dark night sky. Usually, the reflection of city lights off of local air impurities makes it hard for casual observers to see more than a handful of stars from a bright urban area.

M33: Triangulum Galaxy
27.09.2018

The small, northern constellation Triangulum harbors this magnificent face-on spiral galaxy, M33. Its popular names include the Pinwheel Galaxy or just the Triangulum Galaxy. M33 is over 50,000 light-years in diameter, third largest in the Local Group of galaxies after the Andromeda Galaxy (M31), and our own Milky Way.

The Stars of the Triangulum Galaxy
23.02.2019

Like grains of sand on a cosmic beach, stars of the Triangulum Galaxy are resolved in this sharp mosaic from the Hubble Space Telescope's Advanced Camera for Surveys (ACS). The inner region of the galaxy spanning over 17,000 light-years is covered at extreme resolution, the second largest image ever released by Hubble.

X Ray Moon
2.09.2000

This x-ray image of the Moon was made by the orbiting ROSAT (Röntgensatellit) Observatory in 1990. In this digital picture, pixel brightness corresponds to x-ray intensity. Consider the image in three parts: the bright hemisphere of the x-ray moon, the darker half of the moon, and the x-ray sky background.

Sun Halo over Sweden
1.01.2018

What's happened to the Sun? Sometimes it looks like the Sun is being viewed through a giant lens. In the featured video, however, there are actually millions of tiny lenses: ice crystals. Water may freeze in the atmosphere into small, flat, six-sided, ice crystals.

Protoplanetary Survivors in Orion
4.05.2001

The Orion Nebula is a nuturing stellar nursery filled with hot young stars and their natal clouds of gas and dust. But for planetary systems, the active star-forming region can present a hazardous and inhospitable birthplace.

NGC 6946: The Fireworks Galaxy
25.01.2005

Why is this galaxy so active? Nearby spiral galaxy NGC 6946 is undergoing a tremendous burst of star formation with no obvious cause. In many cases spirals light up when interacting with another galaxy, but NGC 6946 appears relatively isolated in space.

The Dance of Venus and Earth
3.06.2020

Every time Venus passes the Earth, it shows the same face. This remarkable fact has been known for only about 50 years, ever since radio telescopes have been able to peer beneath Venus' thick clouds and track its slowly rotating surface. This inferior conjunction -- when Venus and Earth are the closest -- occurs today.