GL 105C: The Coolest Star?
20.09.1995

Is the dim star to the upper right of this false-color picture the coolest possible normal star? From this recent picture by the Hubble Space Telescope, astronomers have estimated its mass is just high enough for it to fuse hydrogen into helium in its core.

The Changing Surface of Fading Betelgeuse
17.02.2020

Besides fading, is Betelgeuse changing its appearance? Yes. The famous red supergiant star in the familiar constellation of Orion is so large that telescopes on Earth can actually resolve its surface -- although just barely.

Saturnian Aurora
17.09.2000

Girdling the second largest planet in the Solar System, Saturn's Rings are one of the most spectacular sights for earthbound telescopes. This image from the orbiting Hubble Space Telescope's STIS instrument, offers a striking view of another kind of ring around Saturn - pole encircling rings of ultraviolet aurora.

Big Mars from Hubble
27.08.2003

At about 10 am Universal Time today, Mars and Earth will pass closer than in nearly 60,000 years. Mars, noticeably red, will be the brightest object in the eastern sky just after sunset.

Highlights of the North Spring Sky
13.03.2019

What can you see in the night sky this season? The featured graphic gives a few highlights for Earth's northern hemisphere. Viewed as a clock face centered at the bottom, early (northern) spring sky events fan out toward the left, while late spring events are projected toward the right.

Vintage Gamma Rays
6.04.2002

Gamma-rays are the most energetic form of electromagnetic radiation. But these high energy photons penetrate and interact in normal materials and cannot be focused by lenses and mirrors like those in optical telescopes. So how do you make an image in gamma-ray light?

Bright Planetary Nebula NGC 7027 from Hubble
26.08.2013

It is one of the brightest planetary nebulae on the sky -- what should it be named? First discovered in 1878, nebula NGC 7027 can be seen toward the constellation of the Swan (Cygnus) with a standard backyard telescope.

In the Heart of the Tarantula Nebula
20.05.2018

In the heart of monstrous Tarantula Nebula lies huge bubbles of energetic gas, long filaments of dark dust, and unusually massive stars. In the center of this heart, is a knot of stars so dense that it was once thought to be a single star.

NGC 4650A: Strange Galaxy and Dark Matter
25.06.1998

This strangely distorted galaxy of stars is cataloged as NGC 4650A. It lies about 165 million light-years away in the southern constellation Centaurus. The complex system seems to have at least two parts, a flattened disk of stars with a dense, bright, central core and a sparse, sharply tilted ring of gas, dust and stars.

Massive Nearby Spiral Galaxy NGC 2841
21.04.2014

It is one of the more massive galaxies known. A mere 46 million light-years distant, spiral galaxy NGC 2841 can be found in the northern constellation of Ursa Major. This sharp view of the gorgeous island universe shows off a striking yellow nucleus and galactic disk.