Pauli Exclusion Principle: Why You Don't Implode
19.02.2003

Why doesn't matter just bunch up? The same principle that keeps neutron stars and white dwarf stars from imploding also keeps people from imploding and makes normal matter mostly empty space. The observed reason is known as the Pauli Exclusion Principle.

NGC 7635: Bubble in a Cosmic Sea
28.04.2006

Seemingly adrift in a cosmic sea of stars and glowing gas, the delicate, floating apparition near the center (next to a blue tinted star) of this widefield view is cataloged as NGC 7635 - The Bubble Nebula.

Globules in the Running Chicken Nebula
5.03.2014

The eggs from this chicken may form into stars. The above pictured emission nebula, cataloged as IC 2944, is called the Running Chicken Nebula for the shape of its greater appearance. The image was taken recently from Siding Spring Observatory in Australia and presented in scientifically assigned colors.

Bright Spiral Galaxy M81
18.11.2014

One of the brightest galaxies in planet Earth's sky is similar in size to our Milky Way Galaxy: big, beautiful M81. This grand spiral galaxy can be found toward the northern constellation of the Great Bear (Ursa Major).

Approaching the Bubble Nebula
31.05.2017

What would it look like to approach the Bubble Nebula? Blown by the wind and radiation from a massive star, this bubble now spans seven light-years in diameter. The hot star inside is thousands of times more luminous than our Sun, and is now offset from the nebula's center.

Messier 20 and 21
24.08.2018

The beautiful Trifid Nebula, also known as Messier 20, is easy to find with a small telescope in the nebula rich constellation Sagittarius. About 5,000 light-years away, the colorful study in cosmic contrasts shares this well-composed, nearly 1 degree wide field with open star cluster Messier 21 (bottom right).

Perihelion to Aphelion
9.01.2020

Perihelion for 2020, the point in Earth's elliptical orbit when it is closest to the Sun, occurred on January 5th. The distance from the Sun doesn't determine the seasons, though. Those...

The Galactic Center in Infrared
19.04.2021

What does the center of our galaxy look like? In visible light, the Milky Way's center is hidden by clouds of obscuring dust and gas. But in this stunning vista, the Spitzer Space Telescope's infrared cameras, penetrate much of the dust revealing the stars of the crowded galactic center region.

APOD: 2023 August 9 Б Meteor Shower: Perseids from Perseus
9.08.2023

This is a good week to see meteors. Comet dust will rain down on planet Earth, streaking through dark skies during peak nights of the annual Perseid Meteor Shower. The featured composite image was taken during the 2018 Perseids from the Poloniny Dark Sky Park in Slovakia.

APOD: 2025 April 23 Б An Almost Everything Sky
23.04.2025

This surprising sky has almost everything. First, slanting down from the upper left and far in the distance is the central band of our Milky Way Galaxy. More modestly, slanting down from the upper right and high in Earth's atmosphere is a bright meteor.