The Observable Universe
8.05.2018

How far can you see? Everything you can see, and everything you could possibly see, right now, assuming your eyes could detect all types of radiations around you -- is the observable universe. In visible...

M13: The Great Globular Cluster in Hercules
19.03.2020

In 1716, English astronomer Edmond Halley noted, "This is but a little Patch, but it shews itself to the naked Eye, when the Sky is serene and the Moon absent." Of course...

APOD: 2023 July 18 Б Milky Way above La Palma Observatory
18.07.2023

What's happening in the night sky? To help find out, telescopes all over the globe will be pointing into deep space. Investigations will include trying to understand the early universe, finding and tracking Earth-menacing asteroids, searching for planets that might contain extra-terrestrial life, and monitoring stars to help better understand our Sun.

APOD: 2025 August 14 Б M13: The Great Globular Cluster in Hercules
14.08.2025

In 1716, English astronomer Edmond Halley noted, "This is but a little Patch, but it shews itself to the naked Eye, when the Sky is serene and the Moon absent." Of course...

Simulated Supergiant Star
22.12.2000

Looking for that perfect holiday gift for an astronomer? Consider this "star in a box". Of course, the box is actually a computational box consisting of a three dimensional grid of points, and the star is a virtual one whose physical properties and internal dynamics are numerically simulated at the points on the grid.

X Rays from the Galactic Core
8.01.2003

Using the orbiting Chandra X-ray Observatory, astronomers have taken this long look at the core of our Milky Way galaxy, some 26,000 light-years away. The spectacular false-color view spans about 130 light-years.

Iridium Flare
2.04.1998

Have you seen an Iridium flare? Satellites in low Earth orbit reflect sunlight and are often visible gliding across early evening and predawn skies. But sun glints from Iridium commercial digital communications satellites are providing the most spectacular sightings.

Celebrating Hubble With NGC 6751
16.04.2005

Planetary nebulae can look simple, round, and planet-like in small telescopes. But images from the orbiting Hubble Space Telescope have become well known for showing these fluorescent gas shrouds of dying Sun-like stars to possess a staggering variety of detailed symmetries and shapes.

Hale Bopp: The Great Comet of 1997
13.10.2013

Sixteen years ago, Comet Hale-Bopp rounded the Sun and offered a dazzling spectacle in planet Earth's night. This stunning view, recorded shortly after the comet's 1997 perihelion passage, features the memorable tails of Hale-Bopp -- a whitish dust tail and blue ion tail.

Heliopause Electrostatic Rapid Transit System
16.04.2016

Want to take a fast trip to the edge of the Solar System? Consider a ride on a Heliopause Electrostatic Rapid Transit System (HERTS). The concept is currently being tested and it might take only 10 to 15 years to make the trip of over 100 Astronomical Units (15 billion kilometers).