Here are 50 facts from FunFact's “Space” topic, all checked. Each one cites its source (science.nasa.gov, nasa.gov, en.wikipedia.org…) and the date it was checked. This topic is part of FunFact Premium.
Asteroids there are separated by huge distances compared with their size.
Space probes have crossed the belt without having to zigzag between rocks.
Source: NASA Science — Asteroid belt · Checked on October 24, 2026
Aleksander Wolszczan and Dale Frail detected planets around PSR B1257+12, about 2,300 light-years away in Virgo.
They were spotted thanks to tiny variations in the rhythm of the pulsar’s radio pulses. These worlds probably formed after the star exploded. Today, more than 6,000 exoplanets are confirmed.
Source: Scientific American — The Exoplanet Revolution Turns 25 · Checked on October 24, 2026
Gravity is stronger on the side closest to the black hole than on the other: the object is stretched lengthwise and squeezed from the sides.
The term was popularized by physicist Stephen Hawking. Around a stellar-mass black hole, the stretching happens before the event horizon. Around a supermassive black hole, you could cross the horizon without feeling anything at first.
Source: NASA Science — What Happens When Something Gets Too Close to a Black Hole? · Checked on October 26, 2026
In full lunar daylight, astronauts in white suits are very bright: the exposure must be short, too brief to capture the faint light of the stars.
Even to the naked eye, the astronauts could not see the stars, because their eyes had adapted to the bright light. It's not a hoax: the same thing shows up in many photos taken in orbit.
Source: NASA — Where are the stars? · Checked on October 26, 2026
The Copernicus program provides its data on forests, ice, floods and soils freely: anyone can download them.
The Sentinel-1 satellites, equipped with radar, see through clouds, day and night. The images are used by rescue services after a flood, for crop monitoring and for tracking melting ice.
Source: eoPortal — Copernicus: Sentinel-1 · Checked on October 24, 2026
The plume of dark material shot out of the frozen surface, and its cloud drifted 150 km (93 miles) in Triton’s winds.
According to NASA, it is probably pressurized nitrogen gas that propels dark particles. Triton is one of the few bodies in the Solar System where eruptions have been seen in progress.
Source: NASA/JPL · Checked on October 26, 2026
As early as 1690, astronomer John Flamsteed had observed it at least six times without understanding: he had logged it as a star, “34 Tauri.”
Under a very dark sky, Uranus is just barely visible to the naked eye. William Herschel spotted it in 1781 when he saw that it moved: at first he thought it was a comet, but it was quickly understood to be a planet.
Source: Astronomy Now — Observe planet Uranus at its best in the autumn sky · Checked on October 24, 2026
Its average density is about 0.687 grams per cubic centimeter, well below that of water.
Made up overwhelmingly of light hydrogen and helium, it would theoretically float if an ocean big enough could be found.
Source: NASA Science — Saturn: Facts · Checked on October 24, 2026
Cospas-Sarsat, born of cooperation among the USSR, the United States, Canada and France, locates distress beacons from ships, aircraft and hikers.
It has helped rescue at least 63,000 people in nearly 20,000 operations between 1982 and 2023. Many beacons activate automatically during a shipwreck or crash. France is one of the four countries behind the program.
Source: CNES — Cospas-Sarsat · Checked on October 24, 2026
The fine red dust floating in the Martian sky filters sunlight in a very special way.
As the Sun sets, this dust lets blue light through and blocks red colors, creating a bluish halo around the Sun.
Source: NASA Science — Mars: Facts · Checked on October 24, 2026
The floors of these craters never see sunlight and stay below about −170 °C (−274 °F, or 102 K): ice can survive there.
Radar suggested it in the 1990s, then NASA's MESSENGER probe confirmed it. Estimates range from 100 billion to 1 trillion metric tons of ice.
Source: LASP, CU Boulder — MESSENGER finds polar ice on Mercury · Checked on October 26, 2026
With no atmosphere to hold in heat, the lunar surface reaches about 127 °C (261 °F) in sunlight and −173 °C (−279 °F) at night, at the equator.
In some polar craters that the Sun never lights, the temperature drops below −240 °C (−400 °F), among the coldest places measured in the Solar System.
Source: UCLA Diviner — LRO Diviner Lunar Radiometer Experiment · Checked on October 24, 2026
At the Moon's distance, Hubble can only make out objects about 100 m (330 ft) across; a flag is roughly 1.5 m (5 ft) long.
Only probes orbiting the Moon manage it: NASA's LRO probe photographs the Apollo sites at a resolution of about 1 m (3 ft), which shows the landing stages.
Source: Sky & Telescope · Checked on October 26, 2026
Mercury is the first planet, but Venus has a thick layer of toxic clouds that acts like a blanket.
This giant greenhouse effect traps the Sun’s heat, pushing Venus’s temperature above 460 °C (860 °F), enough to melt lead.
Source: NASA Science — Venus: Facts · Checked on October 24, 2026
In 2021, it crossed the Alfvén critical surface, entering directly into the Sun’s atmosphere of magnetized plasma.
Protected by a carbon shield twelve centimeters (4.7 in) thick, it skims the Sun at over 600,000 km/h (373,000 mph), an absolute speed record.
Source: NASA Science — Parker Solar Probe · Checked on October 24, 2026
Each galaxy is like a great cosmic city that brings together billions of stars, gas, and dust.
Modern telescopes show us that the parts of the sky we thought were empty are actually filled with countless twinkling galaxies.
Source: NASA Science — Galaxies: Overview · Checked on October 24, 2026
Astronaut Stuart Roosa took seeds of five species (pine, sycamore, sweetgum, redwood, Douglas fir) aboard Apollo 14.
The young trees, called “Moon Trees,” were planted across the United States and in a few other countries. The number of seeds varies by source, from a few hundred to more than 2,000.
Source: NASA · Checked on October 26, 2026
He conceded defeat in 1990 to Kip Thorne, when observations strengthened the case that a black hole was hiding in Cygnus X-1.
Hawking had devoted his career to black holes: the bet was a kind of insurance. If he was wrong about Cygnus X-1, he lost the bet but was right about the essentials. Cygnus X-1 is an X-ray source discovered in 1964.
Source: Astronomy — Cygnus X-1: The black hole that started it all · Checked on October 24, 2026
These cryovolcanoes emit a “cryolava” made of volatile materials. Enceladus, a moon of Saturn, is the most spectacular example observed so far.
Enceladus's jets feed Saturn's E ring. Few cryovolcanoes are confirmed with certainty: many examples, like Triton or Titan, remain hypotheses.
Source: National Geographic Education — Cold Explosion · Checked on October 26, 2026
The power produced at the Sun's center is about 276 watts per cubic meter, very far from the image of a permanent explosion.
The Sun shines mainly because it is gigantic: each part of an immense volume produces just a tiny bit. This slow output lets it last about ten billion years.
Source: ABC Science — Lazy Sun is less energetic than compost · Checked on October 24, 2026
Its slow rotation and fast orbit produce a solar day equal to two Mercury years.
Mercury rotates once on its axis in just 59 Earth days, but it circles the Sun in 88 days, so the Sun takes 176 days to return to the same spot in its sky: exactly two Mercury years.
Source: NASA Science — Mercury: Facts · Checked on October 24, 2026
On June 20, 1944, it crossed the 100 km (62 mi) altitude mark and reached about 175 km (109 mi) (174.6 km, or 108.5 mi, according to Guinness).
A 1942 test had only reached 84.5 km (52.5 mi). The V-2 was a weapon; the 100 km boundary of space (the Kármán line) was set after the war, so the title was awarded after the fact.
Source: Guinness World Records · Checked on October 26, 2026
As of November 2021, 4,584 had been recorded. The distant reservoir of the Oort cloud is thought to contain roughly a trillion bodies of this kind.
Almost all are too far away and too dark to be detected. The figure of a trillion is an estimate of the possible population, not a count.
Source: Wikipédia · Checked on October 26, 2026
Physicist Kip Thorne, the film’s advisor (2014), co-authored with the visual effects team a study on light bent by rotating black holes.
The team calculated the paths of millions of light rays around the film’s black hole, Gargantua. Some realistic effects were deliberately toned down on screen so as not to confuse the audience.
Source: arXiv (James, von Tunzelmann, Franklin, Thorne) · Checked on October 24, 2026
According to NASA, sunlight and the solar wind push material away from the cloud surrounding the nucleus and form these two tails.
The coma is the cloud of gas and dust surrounding the nucleus. The tails point away from the Sun, pushed by its light and by the stream of particles it emits, the solar wind.
Source: NASA : Comets facts · Checked on October 26, 2026
The cable shield of each rover's Rock Abrasion Tool (RAT) comes from aluminum salvaged from the site of the towers after September 11, 2001.
This tool grinds the surface of rocks to look inside them. The original claim spoke of “tools” and pieces of the towers: only the aluminum in one part is confirmed, not steel.
Source: NASA Science — Interplanetary Memorial to Victims of Sept. 11, 2001 · Checked on October 26, 2026
On March 13, 1989, the Hydro-Québec grid collapsed within a few tens of seconds, leaving about six million people without electricity for nine hours.
A solar flare had triggered a powerful geomagnetic storm. It induced currents in the high-voltage lines, which tripped the protective systems. Since then, power operators have monitored space weather.
Source: SolarStorms.org — A Conflagration of Storms · Checked on October 24, 2026
From about ten seconds to twenty minutes after the Big Bang, the Universe was hot enough to fuse protons and neutrons, as in the core of a star.
This “primordial nucleosynthesis” produced mostly hydrogen (about 75% of the mass) and helium (about 25%), with traces of lithium. This proportion, confirmed by observations, is one of the pillars of the Big Bang theory.
Source: Lawrence Berkeley National Laboratory — Big Bang Nucleosynthesis · Checked on October 24, 2026
While watching Uranus pass in front of a star, astronomers saw the star vanish five times before and after the planet's passage.
Elliot, Dunham, and Mink wanted to study Uranus's atmosphere. The star's flickering revealed narrow rings. The telescope was mounted on an airplane, the Kuiper Airborne Observatory.
Source: Nature — The rings of Uranus · Checked on October 26, 2026
Kepler-51b is almost 7 times Earth’s diameter but only 3.5 times its mass: its density is about 0.06 g/cm³.
These planets look more like giant clouds than solid worlds. Astronomers are still trying to explain how they could form without losing their atmosphere.
Source: arXiv — The Featureless Transmission Spectra of Two Super-Puff Planets · Checked on October 24, 2026
Lifting off from Kourou on December 25, 2021, it saved the telescope fuel, so Webb can now operate for far longer than the planned ten years.
Webb uses its own fuel to hold its position 1.5 million km (930,000 mi) from Earth. The launch's precision avoided costly corrections: the team estimates it has fuel for well over ten years of scientific operation.
Source: ESA Webb · Checked on October 24, 2026
The experiment came from a 17-year-old high school student, chosen from more than 3,400 proposals from American high school students.
The spiders, garden orb-weavers (Araneus diadematus), eventually spun webs in weightlessness. One of them, Anita, died during the last week of the mission, which lasted 59 days.
Source: NASA · Checked on October 26, 2026
On December 24, 2024, it passed 6.1 million km (3.8 million mi) from the Sun's surface at 192 km/s (119 mi/s): a trip around the Earth in under 4 minutes.
It speeds up under the Sun's pull as it approaches, like a marble rolling down a bowl. Its carbon shield withstands about 1,400 °C (2,550 °F), while the instruments behind it stay at room temperature.
Source: Guinness World Records · Checked on October 24, 2026
Using the European Very Large Telescope in Chile, they photographed 2M1207 b, a giant planet orbiting a brown dwarf.
The planet is very distant, about 170 light-years away, and shines mainly in infrared. It could be seen because its host, a brown dwarf, is itself very dim. It is generally described as the first exoplanet photographed, even though its status as a planet (about 5 Jupiter masses) is still debated.
Source: Space.com — Fresh Debate over First Photo of Extrasolar Planet · Checked on October 24, 2026
Launched in 1977, the probe crossed the heliopause in August 2012, where the solar wind gives way to particles from our galaxy.
It travels at more than 61,000 km/h (38,000 mph) and still transmits a trickle of scientific data from more than twenty billion kilometers (12 billion mi) from Earth.
Source: NASA JPL — Voyager: The Interstellar Mission · Checked on October 24, 2026
Earth's axis drifts slowly: one full cycle of this motion (precession) takes about 25,770 years.
Today, Polaris is less than 0.5° from the north celestial pole. Around the year 7500 it will be Alderamin, and Vega will take over again around 14,500. In distant antiquity, around 2800 BC, it was Thuban.
Source: Universe Today — The Cepheus Constellation · Checked on October 26, 2026
Observatories on Earth aim beams at glass retroreflectors placed on the Moon by the Apollo and Lunokhod missions.
By timing the photons’ round trip of two and a half seconds, physicists test general relativity.
Source: NASA Science — Earth's Moon: Facts · Checked on October 24, 2026
Landed in January 2004, it traveled more than 45 km (28 mi) and only stopped transmitting in June 2018, during a dust storm.
Its baseline mission lasted 90 Martian days. The wind regularly cleaned its solar panels. After more than a thousand commands went unanswered, NASA declared the mission over in February 2019.
Source: NASA — NASA's Opportunity Rover Mission on Mars Comes to End · Checked on October 24, 2026
Appearing in October 1604 in Ophiuchus, it was brighter than all the stars in the sky and visible in broad daylight for more than three weeks.
It bears the name of Kepler, who studied it, but other observers had seen it before him. For over 400 years, no other has been clearly observed with the naked eye in the Milky Way.
Source: Kepler's Supernova Remnant: A Star's Death Comes to Life — Chandra X-Ray Observatory · Checked on October 24, 2026
The telescope shoots through different filters; each image is assigned a color, then they are layered on top of one another.
Each raw image shows only shades of gray and the color of the filter used. The final colors aren't always what a human eye would see: they can represent invisible wavelengths.
Source: ESA/Hubble · Checked on October 26, 2026
Yet it remains gaseous: the heat and pressure there are immense.
Despite this extreme density, the core temperature of fifteen million degrees keeps matter in the form of a fluid plasma.
Source: NASA Science — Our Sun: Facts · Checked on October 24, 2026
Landers, rovers (including those of Apollo 15, 16 and 17) and Soviet, American, Chinese and Indian probes have stayed there.
The estimate is 187,400 kg (413,000 lb); the detailed table in the list even gives 222,729 kg (491,000 lb) of dry mass. Only a few objects still work, such as the Apollo laser reflectors.
Source: Wikipédia (List of artificial objects on the Moon) · Checked on October 26, 2026
On April 12, 1961, the first man in space returned by parachute, separated from his Vostok 1 capsule, which hit the ground on its own.
The capsule's landing was too rough for a human. The USSR kept this detail quiet for a long time: to certify a record, the rules of the International Aeronautical Federation required the pilot to come back in his craft.
Source: ESA — The flight of Vostok 1 · Checked on October 24, 2026
This trail, invisible to the naked eye, stretches several million kilometers away from the Sun, according to observations made from Earth.
Sunlight (radiation pressure) pushes the sodium atoms torn from Mercury's thin layer of gas toward the back of the planet. It is not an icy tail like those of comets. It was observed in the 2000s and mapped over about 2.5 million km (1.6 million mi) in 2008.
Source: ScienceAlert — Mercury Is a Planet With a Tail. Here's How That's Possible. · Checked on October 24, 2026
On Earth, gravity pulls our tears downward so they run down our cheeks.
In weightlessness, tears simply gather around the eye into a big jelly-like ball of water that stings and blurs vision.
Source: NASA Science — Astronaut Crying in Space · Checked on October 24, 2026
In 1989, the Voyager 2 probe spotted the “Great Dark Spot,” 13,000 km by 6,600 km (8,100 by 4,100 mi). By 1994, Hubble could no longer see it.
The Great Dark Spot seen in 1989 no longer existed in 1994, but Hubble spotted a new dark spot in 1994, then others in 2018. These are swirling storms in the atmosphere of Neptune, an ice giant planet.
Source: NASA Science — Hubble Tracks the Lifecycle of Giant Storms on Neptune · Checked on October 26, 2026
The Meteosat satellites, operated by EUMETSAT, the European weather satellite organization, sit directly above the equator at longitude 0° and see all of Europe and Africa at once.
The first, Meteosat-1, was launched in 1977 under the aegis of ESA. The latest ones, of the third generation, transmit a full image of Earth's disk every 10 minutes.
Source: ESA — A brief history of Meteosat · Checked on October 24, 2026
It is a gas giant made mostly of moving gases and liquids.
Deeper down, the pressure and temperature become so extreme that a spacecraft would be crushed, melted and then vaporized.
Source: NASA Science — Jupiter Facts · Checked on October 24, 2026
Without gravity, body fluids shift toward the head: the back of the eye flattens and the optic nerve swells.
This syndrome, called SANS, often causes farsightedness. It mainly affects long stays and can persist after returning to Earth. Astronauts therefore bring spare glasses.
Source: Eye and Brain — Spaceflight Associated Neuro-Ocular Syndrome (SANS): A Systematic Review and Future… · Checked on October 24, 2026
Venus shines far brighter than any star: its magnitude ranges from −4.9 to −3.0, versus about −1.5 for Sirius, the brightest star.
It reflects a lot of light thanks to its thick clouds and stays close to the Sun: it is seen mostly after sunset or before sunrise, hence its nickname, the “Evening Star” or “Morning Star.”
Source: NASA Science — Venus Facts · Checked on October 26, 2026
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