Star Trails for a Red Planet
30.11.2019

Does Mars have a north star? In long exposures of Earth's night sky, star trails make concentric arcs around the north celestial pole, the direction of our fair planet's axis of rotation. Bright star Polaris is presently the Earth's North Star, close on the sky to Earth's north celestial pole.

The Milky Way Over Paranal
23.01.2007

It's not the sky that's falling. More accurately, the Earth is rising. The Earth's rotation gives a continually changing view to all Earth observers, including those measuring the universe at the Paranal Observatory.

Perihelion and Aphelion
3.07.2009

This year Aphelion, the point in Earth's elliptical orbit when it is farthest from the Sun, occurs tomorrow, July 4th. Of course, that doesn't affect the seasons on our fair planet. Those...

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.

Polaris and the Trail of Comet ZTF
3.02.2023

Stars trace concentric arcs around the North Celestial Pole in this three hour long night sky composite, recorded with a digital camera fixed to a tripod on January 31, near цger, Lleida, Spain. On that date Comet C/2022 E3 (ZTF) was near its northernmost declination in planet Earth's sky.

Geostationary Highway through Orion
16.01.2017

Put a satellite in a circular orbit about 42,000 kilometers from the center of the Earth and it will orbit once in 24 hours. Because that matches Earth's rotation period, it is known as a geosynchronous orbit.

Highest, Tallest, and Closest to the Stars
25.02.2016

Fans of planet Earth probably recognize its highest mountain, the Himalayan Mount Everest, on the left in this 3-panel skyscape of The World at Night. Shrouded in cloud Everest's peak is at 8,848 meters (29,029 feet) elevation above sea level.

Geostationary Highway
20.02.2010

Put a satellite in a circular orbit about 42,000 kilometers from the center of the Earth (36,000 kilometers or so above the surface) and it will orbit once in 24 hours. Because that matches Earth's rotation period, it is known as a geosynchronous orbit.

A Time Lapse Lunar Eclipse
3.11.2004

During last week's lunar eclipse, our Moon appeared to disappear. As the Earth moved between the Moon and the Sun, the Earth's shadow fell on the moon, making it quite dark.

A Lunar Eclipse Over Time
26.01.2000

During last week's lunar eclipse, our Moon appeared to disappear. As the Earth moved between the Moon and the Sun, the Earth's shadow fell on the moon, making it quite dark. In the above photograph, the Earth's rotation caused the Moon and stars to appear as streaks during this four-hour exposure.