APOD: 2025 October 6 Б The Changing Ion Tail of Comet Lemmon
6.10.2025

How does a comet tail change? It depends on the comet. The ion tail of Comet C/2025 A6 (Lemmon) has been changing markedly, as detailed in the featured image sequenced over six days between September 25 and October 4 (left to right) from Texas, USA.

APOD: 2024 June 2 Б Rotating Moon from LRO
2.06.2024

No one, presently, sees the Moon rotate like this. That's because the Earth's moon is tidally locked to the Earth, showing us only one side. Given modern digital technology, however, combined with many detailed images returned by the Lunar Reconnaissance Orbiter (LRO), a high resolution virtual Moon rotation movie has been composed.

Farewell Jupiter
9.03.2003

Next stop: Saturn. The Cassini spacecraft, launched from Earth in 1997, has now swung past Jupiter and should arrive at Saturn in the year 2004. Pictured to the left is a parting shot from Cassini in January that would not have been possible from Earth: Jupiter showing a crescent phase.

A Solar Filament Lifts Off
25.07.2004

Hot gas frequently erupts from the Sun. One such eruption produced the glowing filament pictured above, which was captured in 2000 July by the Earth-orbiting TRACE satellite. The filament, although small compared...

DART: Impact on Asteroid Dimorphos
27.09.2022

Could humanity deflect an asteroid headed for Earth? Yes. Deadly impacts from large asteroids have happened before in Earth's past, sometimes causing mass extinctions of life. To help protect our Earth from some...

Hubble Floats Free
25.05.2009

Why put observatories in space? Most telescopes are on the ground. On the ground, you can deploy a heavier telescope and fix it more easily. The trouble is that Earth-bound telescopes must look through the Earth's atmosphere.

Earths San Andreas Fault
7.12.2000

The Earth's surface is broken. Cracks in the Earth's crust known as faults can run for hundreds of kilometers. These faults are frequently the sites of major earthquakes as the tectonic plates that cover the surface of the Earth shift.

The Powerful Sumatra Andaman Islands Earthquake
2.03.2005

December's 9.0 earthquake has likely shortened Earth's day by about three microseconds and may also have tweaked Earth's rotational wobble. The megathrust earthquake occurred as the Indian tectonic plate slid further beneath the Burma tectonic plate.

Penumbral Eclipse Rising
18.02.2017

As seen from Cocoa Beach Pier, Florida, planet Earth, the Moon rose at sunset on February 10 while gliding through Earth's faint outer shadow. In progress was the first eclipse of 2017, a penumbral lunar eclipse followed in this digital stack of seaside exposures.

Cassini Flyby
26.08.1999

Connect the dots and you'll trace the path of the Cassini spacecraft as it took a final turn by Earth on its way to the outer solar system. The dots (in a horizontal row just below center) are actually successive images of the spacecraft.