A Mercury Transit Music Video from SDO
11.05.2016

What's that small black dot moving across the Sun? Mercury. Possibly the clearest view of Mercury crossing in front of the Sun earlier this week was from Earth orbit. The Solar Dynamics Observatory obtained an uninterrupted vista recording it not only in optical light but also in bands of ultraviolet light.

Fireball over Lake Louise
12.10.2021

What makes a meteor a fireball? First of all, everyone agrees that a fireball is an exceptionally bright meteor. Past that, the International Astronomical Union defines a fireball as a meteor brighter than apparent magnitude -4, which corresponds (roughly) to being brighter than any planet -- as well as bright enough to cast a human-noticeable shadow.

APOD: 2023 August 29 Б Unusual Spiral Galaxy M66 from Webb
29.08.2023

Why isn't spiral galaxy M66 symmetric? Usually, density waves of gas, dust, and newly formed stars circle a spiral galaxy's center and create a nearly symmetric galaxy. The differences between...

M80: A Dense Globular Cluster
7.07.1999

If our Sun were part of M80, the night sky would glow like a jewel box of bright stars. M80, also known as NGC 6093, is one of about 250 globular clusters that survive in our Galaxy.

The X Ray Jets of XTE J1550
8.10.2002

The motion of ultra-fast jets shooting out from a candidate black hole star system have now been documented by observations from the orbiting Chandra X-ray Observatory. In 1998, X-ray source XTE J1550-564 underwent a tremendous outburst.

Blue Stagglers in Globular Clusters
4.11.1997

This old dog is doing new tricks. On the left is ancient globular cluster 47 Tucanae which formed many billions of years ago. On the right is a closeup of its dense stellar center by the Hubble Space Telescope, released last week.

A Spiral Galaxy Gallery
14.03.1998

A progression of beautiful spiral galaxies is illustrated above with three photographs from NASA's Ultraviolet Imaging Telescope (UIT). Flying above the Earth's obscuring layer of atmosphere on the Space Shuttle Columbia during...

White Dwarf Star Spiral
1.06.2005

About 1,600 light-years away, in a binary star system fondly known as J0806, two dense white dwarf stars orbit each other once every 321 seconds. Interpreting x-ray data from the Chandra Observatory astronomers argue that the stars' already impressively short orbital period is steadily getting shorter as the stars spiral closer together.

NGC 1309 and Friends
9.02.2006

A gorgeous spiral galaxy some 100 million light-years distant, NGC 1309 lies on the banks of the constellation Eridanus. NGC 1309 spans about 30,000 light-years, one third the size of our larger Milky Way galaxy.

Simulated Gamma ray Sky
31.05.2006

Scheduled for launch in 2007, the Gamma-ray Large Area Space Telescope (GLAST) will explore the Universe in gamma-rays, the most energetic form of light. To get ready, consider this dynamic gamma-ray sky animation - constructed from simulating the first 55 days (seen above at one frame per day) of GLAST observations of cosmic gamma-ray sources.