Space

396 cards. Each one is a 40-second story with a five-minute read behind it. Page 7 of 7.

Betelgeuse owes its famous name to a medieval misreading of ArabicThe Arabic name meant the hand of al-Jawzā, the figure we call Orion. Around the thirteenth century a European scribe misread a single dotted letter, turning a y sound into a b, a…
Everything around you survived a cosmic wipeout by a margin of one in thirty millionIn the searing first instants after the Big Bang, matter and antimatter were created and destroyed in almost equal amounts. Some unknown process tipped the balance by about one pa…
Astronomers keep five different maps of the sky, each drawn around a different equatorThere is no single address for a star. Astronomers choose among several coordinate systems, each built around a different great circle that splits the sky in half: your own horizo…
The farthest thing most eyes can see is a whole other galaxyOn a moonless night you can spot a faint smudge in the constellation Andromeda without any telescope. That blur is a spiral galaxy about 2.5 million light-years away, larger acros…
Arcturus was the first star besides the Sun seen through a telescope in daylightIn 1635 the French astronomer Jean-Baptiste Morin trained a telescope on Arcturus in broad daylight and saw it, the first recorded daytime sighting of any star apart from the Sun …
Every asteroid in the main belt combined weighs just 3 percent of our MoonRoughly a million asteroids are known, most circling between Mars and Jupiter, yet pile them all together and they would make only 3 percent of the Moon. The first was found by ac…
The asteroid belt is so empty that spacecraft fly through it unharmedFilms show the asteroid belt as a crowded field of tumbling rocks. In reality its known members sit about a million kilometres apart on average, and many uncrewed probes have cros…
By 1900, astronomers had measured the distances to only about 60 starsPinning down exactly where a star sits sounds dull until you learn that nobody managed a single stellar parallax until Friedrich Bessel. Astrometry, the science of star positions,…
The farthest thing most backyard telescopes will ever show you is a quasarPoint a modest 6-inch telescope at Virgo between March and July and you can catch 3C 273, light that left a feeding black hole about 2.4 billion years ago. It was the first quasar…
The brightest steady lights in the cosmos are black holes eatingSome galaxy centres blaze across every kind of light, from radio waves to gamma rays, far brighter than their stars could manage. These active galactic nuclei are the most luminou…
How much sunlight a planet bounces back can swing its temperature by tens of degreesEarth reflects about 30 percent of incoming sunlight, largely thanks to clouds. That share, called albedo, helps hold the average surface near 15 degrees Celsius. Freeze the whole…
The nearest star is invisible to the naked eye, but its neighbours shine brightlyAlpha Centauri looks like one brilliant star, the third brightest in the night sky. It is really three. Two Sun-like stars circle each other every 79 years, and a faint red dwarf …
In 1998 astronomers found the universe's expansion is speeding up, not slowing.Everyone expected gravity to be gradually slowing the expansion of the universe. Two rival teams set out to measure how much, using exploding stars as distance markers. Both found…
Apollo 13's crew got home using a lunar lander as a lifeboat.Two days into the flight to the Moon in April 1970, an oxygen tank exploded and crippled Apollo 13's main spacecraft. The three astronauts retreated into their small lunar lander,…
Two astronomers cleaned pigeon droppings from their antenna and found the Big Bang's afterglow.In 1964 two radio astronomers at Bell Labs could not get rid of a faint hiss in their antenna. They evicted nesting pigeons and cleaned out their droppings, but it stayed. It was …
Under the ice of Jupiter's moon Europa lies a hidden ocean.Europa, a moon slightly smaller than ours, is the smoothest solid object known in the Solar System. Its young, cracked ice sits on top of what scientists broadly agree is a salty …
To photograph a black hole, astronomers turned Earth into one giant telescope.A black hole's shadow is tiny as seen from Earth, far too small for any single telescope. So astronomers linked radio dishes across the planet, synchronised with atomic clocks, in…
If aliens are likely, where is everybody? A lunchtime question with no answer.In 1950, walking to lunch at Los Alamos, the physicist Enrico Fermi suddenly asked his colleagues, 'Where is everybody?' Everyone knew he meant aliens. Billions of Sun-like stars,…
Galaxies spin too fast for the matter we can see to hold them together.In the Solar System, outer planets orbit more slowly than inner ones. Astronomers expected the same in spiral galaxies. Instead, Vera Rubin and Kent Ford found in the 1970s that o…
Two black holes collided and stretched Earth by a fraction of a proton.On 14 September 2015 a tremor in spacetime, sent out by two black holes merging over a billion light-years away, passed through Earth. Two detectors in the US caught it, a change …
Jupiter's Great Red Spot is a storm bigger than Earth, and it is shrinking.Jupiter's famous red spot is a vast storm with winds up to about 500 km/h, watched continuously since 1878. A century ago it was around three times Earth's width. Now it is not mu…
Edmond Halley predicted his comet's return but died before it came back.In 1705 Edmond Halley used Newton's new laws of gravity to argue that comets seen in 1531, 1607 and 1682 were one object returning roughly every 76 years. He predicted it would co…
Black holes are not quite black. Given time, they should evaporate.Nothing escapes a black hole, or so physics said until 1974. Then Stephen Hawking combined quantum theory with gravity and found that black holes should glow faintly and slowly sh…
Hubble stared at a tiny empty patch of sky and found 3,000 galaxies.In December 1995 the Hubble Space Telescope spent ten days staring at a speck of sky in Ursa Major, about the size of a tennis ball seen from 100 metres, chosen because almost not…
Nobody can agree where space actually begins.The usual answer is 100 kilometres up, a boundary called the Kármán line. But the atmosphere does not stop anywhere, the US uses 80 kilometres to award astronaut wings, and there …
Space junk could trigger a chain reaction that closes off orbits for generations.In 1978 NASA scientist Donald Kessler warned that if enough debris built up in low Earth orbit, collisions would create more debris, causing more collisions, in a runaway cascade.…
A sugar cube of neutron star weighs about as much as every human alive.When a giant star collapses, it can crush more than the Sun's mass into a ball about the width of a city. The matter is so dense that one cubic centimetre weighs hundreds of milli…
Why is the night sky dark? The answer reaches back to the Big Bang.If the universe were infinite, eternal and full of stars, every line of sight would end on a star, and the night sky would blaze like the surface of the Sun. It doesn't. The darkn…
Mars has a volcano so wide you couldn't see its summit from its slopes.Olympus Mons on Mars rises more than 21 kilometres, roughly two and a half times the height of Everest, and covers an area about the size of Italy. Its slopes are so gentle and br…
In 2017 a visitor from another star system raced through ours.ʻOumuamua was the first object ever confirmed to come from beyond the Solar System. It was spotted in October 2017, already on its way out. It was oddly elongated, had no comet ta…
Pluto was demoted by the votes of 424 astronomers in Prague.In August 2006 the International Astronomical Union defined 'planet' for the first time, and Pluto no longer qualified. The decision was taken on the last day of a conference, by …
The Moon shows us one face because Earth's gravity slowed its spin.The Moon turns exactly once for every orbit, so the same side always faces Earth. That is no coincidence: tides raised by Earth's gravity braked its spin long ago. The Moon is doi…
Saturn's moon Titan has rain, rivers and seas, but they are liquid methane.Titan is the only moon with a thick atmosphere, and the only place besides Earth known to have stable lakes and seas on its surface. At about −179°C, its rain and rivers are made …
In 1908 something exploded over Siberia and flattened a forest, leaving no crater.One summer morning in 1908, a blinding fireball crossed the Siberian sky and exploded above the forest near the Tunguska River. The blast flattened trees over more than 2,000 squa…
On Venus, a day lasts longer than a year.Venus takes 243 Earth days to spin once on its axis, but only 225 days to orbit the Sun. It also spins backwards compared with most planets, so if you could see through its crushi…
In 1977 a radio telescope caught 72 seconds that still have no explanation.In August 1977 an Ohio radio telescope searching for alien signals recorded a strong, narrow burst near the frequency of hydrogen, exactly as a signal from space should look. The …