Space — Page 4

The footprints left on the Moon by Apollo astronauts will likely remain there for millions of years.

The Moon has no atmosphere, wind, or liquid water, which are the main agents of erosion on Earth. Without these…

There is a giant cloud of alcohol in space, specifically ethyl alcohol, near the center of the Milky Way.

Astronomers have detected a massive molecular cloud in the Sagittarius B2 region, near the center of our galaxy. This…

The Sun loses millions of tons of mass every second.

Through nuclear fusion and solar wind, our star constantly converts and ejects matter into space, although this loss…

On Pluto, it snows methane on the highest mountains.

The dwarf planet's thin atmosphere contains methane that freezes and falls as snow in elevated regions, creating a…

Jupiter shrinks by about two centimetres every year.

The planet's huge mass generates strong gravitational compression, and the slow loss of internal heat causes the gas…

Venus is hotter than Mercury, even though it is further from the Sun.

The dense atmosphere of Venus is composed mostly of carbon dioxide, creating an extreme greenhouse effect that traps…

A year on Pluto is equivalent to two hundred and forty-eight Earth years.

Due to its enormous distance from the Sun and its elliptical orbit, the dwarf planet moves very slowly, taking over…

The largest known structure in the universe is the Hercules-Corona Borealis Great Wall.

This massive galactic filament is about ten billion light-years long and contains thousands of galaxy superclusters…

A teaspoon of a neutron star would weigh about 6 billion tons.

Neutron stars are the collapsed cores of massive stars. Gravity crushes matter so forcefully that protons and…

Uranus was the first planet discovered with a telescope, in 1781.

Mercury, Venus, Mars, Jupiter and Saturn are visible to the naked eye and had been known since ancient times. The…

Neptune was discovered in 1846 thanks to mathematical calculations, before anyone saw it through a telescope.

Uranus was not following its predicted orbit exactly, as if something were pulling on it. The Frenchman Urbain Le…

Ganymede, a moon of Jupiter, is larger than the planet Mercury.

At 5,268 km across, Ganymede is the largest moon in the Solar System, compared with Mercury's 4,879 km. Even so, it…

Titan, a moon of Saturn, is the only moon in the Solar System with a thick atmosphere.

Titan's atmosphere is mostly nitrogen, like Earth's, and the pressure at the surface is about one and a half times…

The Voyager 1 probe, launched in 1977, is the human-made object farthest from Earth.

In 2012 it left the bubble of solar wind surrounding the planets and entered interstellar space. It is more than 24…

The Andromeda galaxy, 2.5 million light-years away, is the most distant object easily seen with the naked eye.

Under a dark sky it appears as a faint, elongated smudge. The light we see left it about 2.5 million years ago, when…

Mimas, a moon of Saturn, has a crater so big that it looks like the Death Star from Star Wars.

Herschel crater is about 139 km wide, roughly a third of the moon's entire diameter. The impact that made it nearly…

A comet's tail always points away from the Sun, even when the comet is moving away from it.

The tail is not a trail left behind by motion: it is gas and dust pushed by the solar wind and the pressure of…

The Earth is closest to the Sun in early January, in the middle of the northern hemisphere's winter.

At that point the Earth is about 147 million km from the Sun; in early July it is about 152 million km away. The…

Mercury has a tail of sodium atoms millions of kilometres long, similar to a comet's.

Sunlight and micrometeorite impacts knock sodium atoms off the surface, and the pressure of sunlight pushes them…

Phobos, Mars's largest moon, gets closer to the planet every year and will eventually be torn apart.

Phobos orbits so close to Mars that gravity is slowly braking it: it drops about 1.8 metres per century. In 30 to 50…