Zooming in on the First Stars
10.06.2003

What became of the first stars? No known stars appear to be composed of truly primordial gas -- all of the stars around us have too many heavy elements. Our own Sun is thought to be a third generation star, with many second-generation stars seen in globular clusters.

P2010 A2: Unusual Asteroid Tail Implies Powerful Collision
3.02.2010

What is this strange object? First discovered on ground based LINEAR images on January 6, the object appeared unusual enough to investigate further with the Hubble Space Telescope last week. Pictured above, what Hubble saw indicates that P/2010 A2 is unlike any object ever seen before.

T Tauri: A Star is Formed
3.08.2009

What does a star look like when it is forming? The prototypical example is the variable star T Tauri, visible as the bright orange star near the image center. The orange star centered in this remarkable telescopic skyview is T Tauri, prototype of the class of T Tauri variable stars.

Mira Over Germany
21.02.2007

What's that new star in the sky? The star might appear new, but it's actually just the variable star Mira near its brightest. Rolling your cursor over the above vertically compressed image...

Symbiotic R Aquarii
29.06.2017

A long recognized naked-eye variable star, R Aquarii is actually an interacting binary star system, two stars that seem to have a close, symbiotic relationship. About 710 light years away, it consists of a cool red giant star and hot, dense white dwarf star in mutual orbit around their common center of mass.

Lyman Alpha Blob
2.07.2009

Dubbed a Lyman-alpha blob, an enormous cloud of hydrogen gas spans several hundred thousand light-years in this remarkable image (left), a composite of x-ray, optical, and infrared data from space and ground based observatories.

A Young Supernova in the Nearby Pinwheel Galaxy
26.08.2011

A nearby star has exploded and telescopes all over the world are turning to monitor it. The supernova, dubbed PTF 11kly, was discovered by computer only two days ago as part of the Palomar Transit Factory (PTF) sky survey utilizing the wide angle 1.2-meter Samuel Oschwin Telescope in California.

APOD Turns Eighteen
16.06.2013

The first APOD appeared eighteen years ago today, on 1995 June 16. Although garnering only 14 pageviews on that day, we are proud to estimate that APOD has now served over one billion space-related images over the past eighteen years.

NGC 3239 and SN 2012A
27.01.2012

About 40,000 light-years across, pretty, irregular galaxy NGC 3239 lies near the center of this lovely field of galaxies in the galaxy rich constellation Leo. At a distance of only 25 million light-years...

Galaxy Cluster Gas Creates Hole in Microwave Background
10.04.2017

Why would this cluster of galaxy punch a hole in the cosmic microwave background (CMB)? First, the famous CMB was created by cooling gas in the early universe and flies right through most gas and dust in the universe. It is all around us.