Doomed Star Eta Carinae
26.03.2006

Eta Carinae may be about to explode. But no one knows when - it may be next year, it may be one million years from now. Eta Carinae's mass - about 100 times greater than our Sun - makes it an excellent candidate for a full blown supernova.

The Sun in X rays from NuSTAR
28.12.2014

Why are the regions above sunspots so hot? Sunspots themselves are a bit cooler than the surrounding solar surface because the magnetic fields that create them reduce convective heating. It is therefore unusual that regions overhead -- even much higher up in the Sun's corona -- can be hundreds of times hotter.

APOD: 2025 October 19 Б Comet Churyumov Gerasimenko Creates Its Tails
19.10.2025

Where do comet tails come from? There are usually no obvious places on the nuclei of comets from which the jets that create comet tails emanate. One of the best images of emerging jets...

Behind Saturn
1.08.2016

What's behind Saturn? The first answer is the camera itself, perched on the Cassini spacecraft currently orbiting behind the planet with the most grand ring system in our Solar System. The unusual perspective...

Super Moon vs Micro Moon
13.11.2016

What is so super about tomorrow's supermoon? Tomorrow, a full moon will occur that appears slightly larger and brighter than usual. The reason is that the Moon's fully illuminated phase occurs within a short time from perigee - when the Moon is its closest to the Earth in its elliptical orbit.

APOD: 2024 May 12 Б Red Aurora over Poland
12.05.2024

Northern lights don't usually reach this far south. Magnetic chaos in the Sun's huge Active Region 3664, however, produced a surface explosion that sent a burst of electrons, protons, and more massive, charged nuclei into the Solar System.

GRB 980703: A Reassuring Redshift
13.07.1998

In the old days, just over a year ago, astronomers had little idea of the true distance to gamma-ray bursts. Did these enigmatic explosions occur in our outer Galaxy, or in the outer Universe?

Greeley Panorama on Mars
9.07.2012

What did you do over your winter vacation? If you were the Opportunity rover on Mars, you spent four months of it stationary and perched on the northern slope of Greeley Haven -- and tilted so that your solar panels could absorb as much sunlight as possible.

APOD: 2023 July 9 Б Doomed Star Eta Carinae
9.07.2023

Eta Carinae may be about to explode. But no one knows when - it may be next year, it may be one million years from now. Eta Carinae's mass - about 100 times greater than our Sun - makes it an excellent candidate for a full blown supernova.

APOD: 2026 July 19 Б Flying Saucer Crash Lands in Utah Desert
19.07.2026

A flying saucer from outer space crash-landed in the Utah desert after being tracked by radar and chased by helicopters. The year was 2004, and no space aliens were involved. The saucer, pictured here...