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.

A Busy Space Walk at the Space Station
18.07.2011

What's that astronaut doing? Unloading a space shuttle -- for the last time. After the space shuttle Atlantis docked with the Mike Fossum underwent a long spacewalk that included carrying a Robotics Refueling Mission (RRM) payload from Atlantis' cargo bay to a platform used by the space station's famous robot DEXTRE.

Pauli Exclusion Principle: Why You Don't Implode
28.02.2010

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.

The Rotten Egg Planetary Nebula
1.11.1999

Not all evolving stars eject gas clouds that look like people. OH231.8+4.2 was a star much like our Sun that ran out of nuclear fuel to fuse in its core.

Sher 25: A Pending Supernova?
12.08.1997

No supernova has ever been predicted - yet. These dramatic stellar explosions that destroy stars, that create and disperse the elements that compose people and planets, that light up the night sky, are not so well understood that astronomers can accurately predict when a star will explode - yet. Perhaps Sher 25 will be the first.

Sunrise Solstice at Stonehenge
21.06.2006

Today the Sun reaches its northernmost point in the planet Earth's sky. Called a solstice, the date traditionally marks a change of seasons -- from spring to summer in Earth's Northern Hemisphere and from fall to winter in Earth's Southern Hemisphere. Pictured above is the 2005 Summer Solstice celebration at Stonehenge in England.

APOD: 2026 April 29 Б The Moon, Venus, and the Pleiades
29.04.2026

No, Earth did not recently acquire six more moons! TodayБs APOD is a combination of images following the Moon, Venus, and the Pleiades across a southern Sicilian sky as twilight turned to evening on April 19.

Atlantis Last Approach
13.07.2011

For the last time, the US Space Shuttle has approached the International Space Station (ISS). Following a dramatic launch from Cape Canaveral last week that was witnessed by an estimated one million people, Space Shuttle Atlantis on STS-135 lifted a small crew to a welcome rendezvous three days ago with the orbiting station.

APOD: 2020 August 5 Б Picture Rocks Sun Dagger
5.08.2020

Ancient sun daggers will not hurt you, but they may tell you the time.б A sun dagger is a dagger-shaped gap in a shadow created by sunlight streaming throughбa crevice in a nearby rock.

Eclipse Across America: Path Prediction Video
19.06.2017

Where will you be during the Eclipse across America? On August 21, the shadow of the Moon will cross the continental USA for the first time since 1979. The predicted path -- a certainty given modern astronomical knowledge -- is shown in the featured NASA video.