Ninety Gravitational Wave Spectrograms and Counting
7.12.2021

Every time two massive black holes collide, a loud chirping sound is broadcast out into the universe in gravitational waves. Humanity has only had the technology to hear these unusual chirps for the past seven years, but since then we have heard about 90 -- during the first three observing runs.

Eclipse Over Acacia
3.12.2002

On December 4th, for the second time in as many years, the Moon's shadow will track across southern Africa bringing a total solar eclipse to African skies. Reaching Africa just before...

NGC 1818: Pick A Star
15.04.1998

This is NGC 1818, a youthful, glittering cluster of 20,000 stars residing in the Large Magellanic Cloud, 164,000 light-years away. Pick a star. Any star. Astronomers might pick the unassuming bluish-white one (circled) which appears to be a hot newly formed white dwarf star. What makes it so interesting?

Resolving Mira
11.10.1998

Most stars appear only as points of light. Early last year, Betelgeuse became the second star, after our Sun, to have it surface resolved. Later last year, Mira was added to the list. Mira...

Meteor Over Crater Lake
22.04.2018

Did you see it? One of the more common questions during a meteor shower occurs because the time it takes for a meteor to flash is typically less than the time it takes for a head to turn.

A Ring of Fire Sunrise Solar Eclipse
15.06.2020

What's rising above the horizon behind those clouds? It's the Sun. Most sunrises don't look like this, though, because most sunrises don't include the Moon. In the early morning of 2013 May 10, however, from Western Australia, the Moon was between the Earth and the rising Sun.

Solstice Celebration
21.12.2002

Aloha and Season's greetings! On December 22nd, at 01:14 Universal Time (December 21, 3:14pm Hawaii-Aleutian Standard Time), the Sun reaches its southernmost point in planet Earth's sky marking the final season change for the year 2002. In celebration, consider this delightfully detailed, brightly colored image of the active Sun.

Moon Slide Slim
15.05.2003

No special filters - or even a telescope - are required to enjoy a leisurely lunar eclipse. In fact, watched from all over the night side of planet Earth, these regular celestial performances have entertained many casual skygazers. Still, this eye-catching picture of a lunar eclipse may look unfamiliar.

APOD: 2025 June 2 Б Veil Nebula: Wisps of an Ancient Supernova
2.06.2025

Wisps like this are all that remain visible of a Milky Way star. About 7,000 years ago that star exploded in a supernova, leaving the Veil Nebula. At the time, the expanding cloud was likely as bright as a crescent Moon, remaining visible for weeks to people living at the dawn of recorded history.

NGC 1818: Pick A Star
31.05.2003

This is NGC 1818, a youthful, glittering cluster of 20,000 stars residing in the Large Magellanic Cloud, 180,000 light-years away. Pick a star. Any star. Astronomers might pick the unassuming bluish-white one (circled) which appears to be a hot newly formed white dwarf star. What makes it so interesting?