Hydrogen, Helium, and the Stars of M10
30.06.2001

Stars like the Sun use hydrogen for fuel, "burning" hydrogen into helium at their cores through nuclear fusion. But what happens when that hydrogen runs out? For a while, hydrogen burns in a shell surrounding the stellar core and the star expands to become a red giant.

Unwinding M51
6.04.2024

The arms of a grand design spiral galaxy 60,000 light-years across are unwound in this digital transformation of the magnificent 2005 Hubble Space Telescope portrait of M51. In fact...

NGC6366 vs 47 Ophiuchi
23.05.2025

Most globular star clusters roam the halo of our Milky Way galaxy, but globular cluster NGC 6366 lies close to the galactic plane. About 12,000 light-years away toward the constellation Ophiuchus, the cluster's starlight is dimmed and reddened by the Milky Way's interstellar dust when viewed from planet Earth.

Hydrogen, Helium, and the Stars of M10
12.03.1999

Stars like the Sun use hydrogen for fuel, "burning" hydrogen into helium at their cores through nuclear fusion. But what happens when that hydrogen runs out? For a while, hydrogen burns in a shell surrounding the stellar core and the star expands to become a red giant.

NGC 6357: The Lobster Nebula
28.10.2020

Why is the Lobster Nebula forming some of the most massive stars known? No one is yet sure. Cataloged as NGC 6357, the Lobster Nebula houses the open star cluster Pismis 24 near its center -- a home to unusually bright and massive stars.

Andromeda Island Universe
9.01.2010

The most distant object easily visible to the eye is M31, the great Andromeda Galaxy some two and a half million light-years away. But without a telescope, even this immense spiral galaxy - spanning over 200,000 light years - appears as a faint, nebulous cloud in the constellation Andromeda.

A Cosmic Triangle
15.04.2020

It was an astronomical triple play. Setting on the left, just after sunset near the end of last month, was our Moon -- showing a bright crescent phase. Setting on the right was Venus, the brightest planet in the evening sky last month -- and this month, too.

Stardust in Perseus
10.10.2015

This cosmic expanse of dust, gas, and stars covers some 6 degrees on the sky in the heroic constellation Perseus. At upper left in the gorgeous skyscape is the intriguing young star cluster IC 348 and neighboring Flying Ghost Nebula.

Constellation Construction
20.07.2006

This lovely twilight scene, recorded last April, finds a young crescent Moon low in the west at sunset. Above it, stars shine in the darkening sky but they too are soon to drop below the western horizon.

VAR
1.07.2011

In the 1920s, examining photographic plates from the Mt. Wilson Observatory's 100 inch telescope, Edwin Hubble determined the distance to the Andromeda Nebula, decisively demonstrating the existence of other galaxies far beyond the Milky Way.