APOD: 2026 August 4 Б Curious Cometary Knots in the Helix Nebula
3.08.2026

What causes unusual knots of gas and dust in planetary nebulas? Seen also in the Ring Nebula, the Dumbbell Nebula and NGC 2392, the knots' existence was not initially predicted, and their origins are still not well understood.

A Perseid Meteor
12.08.2000

This weekend, the annual Perseid Meteor Shower reaches its maximum. Grains of cosmic sand and gravel shed from Comet Swift-Tuttle will streak across the sky as they vaporize during entry into Earth's atmosphere. The Perseids result from the yearly

The Galactic Center A Radio Mystery
3.08.2002

Tuning in to the center of our Milky Way galaxy, radio astronomers explore a complex, mysterious place. A premier high resolution view, this startlingly beautiful picture covers a 4x4 degree region around the galactic center.

X Ray Triple Jet
31.07.1999

Recorded on July 7, 1998, this animation using X-ray images of the Sun shows an amazing event - three nearly simultaneous jets connected with solar active regions. The two frames were taken several hours apart by the Soft X-ray Telescope on board the orbiting Yohkoh observatory.

The Bloop: A Mysterious Sound from the Deep Ocean
27.04.2010

What created this strange sound in Earth's Pacific Ocean? Pictured above is a visual representation of a loud and unusual sound, dubbed a Bloop, captured by deep sea microphones in 1997. In the above graph, time is shown on the horizontal axis, deep pitch is shown on the vertical axis, and brightness designates loudness.

NGC 7293: The Helix Nebula
10.05.2003

Will our Sun look like this one day? The Helix Nebula is the closest example of a planetary nebula created at the end of the life of a Sun-like star. The outer gasses of the star expelled into space appear from our vantage point as if we are looking down a helix.

Mystery Feature Now Disappears in Titan Lake
6.03.2016

What is that changing object in a cold hydrocarbon sea of Titan? Radar images from the robotic Cassini spacecraft orbiting Saturn have been recording the surface of the cloud-engulfed moon Titan for years. When...

APOD: 2026 March 5 Б Total Lunar Eclipse over Tse Bitai
4.03.2026

Earlier this week, EarthБs shadow swept across the full Moon in the yearБs only total lunar eclipse. This stunning sequence combines images showing the MoonБs path across the night sky. Each lunar image captures our planetБs shadow gradually engulfing the Moon, culminating in its red glow.

Asteroid Vesta Full Frame
2.08.2011

Why is the northern half of asteroid Vesta more heavily cratered than the south? No one is yet sure. This unexpected mystery has come to light only in the past few weeks since the robotic Dawn mission became the first spacecraft to orbit the second largest object in the asteroid belt between Mars and Jupiter.

Stickney Crater
18.01.2013

Stickney Crater, the largest crater on the martian moon Phobos, is named for Chloe Angeline Stickney Hall, mathematician and wife of astronomer Asaph Hall. Asaph Hall discovered both the Red Planet's moons in 1877.