Equinox on a Spinning Earth
21.09.2021

When does the line between night and day become vertical? Today. Today is an equinox on planet Earth, a time of year when day and night are most nearly equal. At an equinox, the Earth's terminator -- the dividing line between day and night -- becomes vertical and connects the north and south poles.

A Message from Earth
2.05.2020

What are these Earthlings trying to tell us? The featured message was broadcast from Earth towards the globular star cluster M13 in 1974. During the dedication of the Arecibo Observatory - still one of the largest single radio telescopes in the world - a string of 1's and 0's representing the diagram was sent.

Earth and Moon through Saturns Rings
26.05.2020

What are those dots between Saturn's rings? Our Earth and Moon. Just over three years ago, because the Sun was temporarily blocked by the body of Saturn, the robotic Cassini spacecraft was able to look toward the inner Solar System.

Blue Marble Earth
5.02.2022

Welcome to planet Earth, the third planet from a star named the Sun. The Earth is shaped like a sphere and composed mostly of rock. Over 70 percent of the Earth's surface is water. The planet has a relatively thin atmosphere composed mostly of nitrogen and oxygen.

Cyclone Paths on Planet Earth
14.09.2021

Where on Earth do cyclones go? Known as hurricanes when in the Atlantic Ocean and typhoons when in the Pacific, the featured map shows the path of all major storms from 1985 through 2005. The map shows graphically that cyclones usually occur over water, which makes sense since evaporating warm water gives them energy.

The Dance of Venus and Earth
2.06.2020

Every time Venus passes the Earth, it shows the same face. This remarkable fact has been known for only about 50 years, ever since radio telescopes have been able to peer beneath Venus' thick clouds and track its slowly rotating surface. This inferior conjunction -- when Venus and Earth are the closest -- occurs today.

GRACE Maps the Gravity of Earth
23.07.2003

Why do some places on Earth have higher gravity than others? Sometimes the reason is unknown. To help better understand the Earth's surface, slight distance changes between a pair of identically orbiting satellites named GRACE have been used to create the best ever map of Earth's gravitational field.

Where People Live on Planet Earth
4.03.2003

Where do people live on Planet Earth? Although people inhabit every continent, the highest population densities occur in Asia. Sparsely inhabited regions occur on virtually every continent, however, including the Sahara Desert in Africa...

Terkezi Oasis in the Sahara Desert
11.11.2002

Dominating the top third of Africa is the largest band of dry land on Earth: the Sahara Desert. Stretching across the Sahara are vast planes of sand and gravel, seas of sand dunes, and barren rocky mountains.

An Earth Ornament
24.12.1996

The Apollo 8 astronauts spent the 1968 Christmas Season in lunar orbit, returning with striking images of the Moon and Earth from space which inspired the world. While in lunar orbit...