@XFactBook

Daily odd science & curious facts. Always true. Never boring.

Joined September 2026
  • Tweets367
  • Following278
  • Followers9
29Media
Did you know a sugar cube of neutron star would weigh about a billion tons on Earth? That's roughly a mountain. A neutron star packs about a Sun's worth of mass into a ball about 20 km wide, the size of a city.
Diagram of a pulsar: a spinning neutron star in the centre with magnetic field lines looping around it and beams of radiation shooting out from its magnetic poles.

ALT Diagram of a pulsar: a spinning neutron star in the centre with magnetic field lines looping around it and beams of radiation shooting out from its magnetic poles.

2
1
1
8
Bonus: in metric that sugar cube is about 1 trillion kilograms. The whole star is only about 12.5 miles across.
3
Source: NASA Imagine the Universe: Neutron Stars imagine.gsfc.nasa.gov/scienc…
4
The question started as lunch chat. At Los Alamos in 1950, Enrico Fermi and colleagues joked about a New Yorker cartoon of aliens stealing trash cans. Later, out of the blue, he asked "But where is everybody?" and the whole table knew he meant aliens.
National Geographic
@NatGeo13h
Why haven't we found any evidence of alien civilizations? The answer could be simple. Discover more about LOST IN SPACE: 5,000 Facts for Navigating the Universe: on.natgeo.com/93P5vi
9
XFacts retweeted
OnThisDay@X_OnThisDay14h
On this day in 1959, the Guggenheim opened in New York, and Frank Lloyd Wright wasn't there to see it. He'd died six months earlier. Beforehand, 21 artists signed a letter protesting their work hanging on his spiral ramp. Visitors didn't care: 600 an hour poured in. #OnThisDay
1966 US 2-cent postage stamp showing Frank Lloyd Wright's portrait with the spiral Guggenheim Museum behind him

ALT 1966 US 2-cent postage stamp showing Frank Lloyd Wright's portrait with the spiral Guggenheim Museum behind him

1
1
1
6
See the brightest star, Sirius, in your morning sky! 🌟🌌 Before daybreak, look for #Sirius. It’s so bright that you can see it from a light-polluted city. It’s rising in the middle of the night and best seen by dawn. buff.ly/sif9VQE 📸 EarthSky.org.
Star chart with Orion and arrow from 3-star Belt to lone star Sirius below.

ALT Star chart with Orion and arrow from 3-star Belt to lone star Sirius below.

1
18
61
2,221
If Tim Burton had a favorite cephalopod, it might be this one. Meet the striped pyjama squid! One of the few known poisonous cephalopods, this critter can change color & secrete slime to intimidate foes. It spends its days nestled beneath the sand, hunting for prey by night.
A photo of a striped pyjama squid. Its skin has a pattern of white and maroon stripes.

ALT A photo of a striped pyjama squid. Its skin has a pattern of white and maroon stripes.

3
30
2
178
4,199
The SOAR Telescope looks like a giant snowball nestled in the foothills of the Chilean Andes. ❄️🏔️ Beneath its distinctive dome, a 4.1-meter telescope uses adaptive optics to capture sharp views of stars, galaxies, and fleeting cosmic events. 📷 NOIRLab/NSF/AURA/C. Corco
2
8
1
56
1,248
Despite the name, the striped pyjama squid isn't a true squid. It's a bottletail squid, more closely related to cuttlefish, and it lives only in the waters off southern Australia.
American Museum of Natural History
@AMNH20h
If Tim Burton had a favorite cephalopod, it might be this one. Meet the striped pyjama squid! One of the few known poisonous cephalopods, this critter can change color & secrete slime to intimidate foes. It spends its days nestled beneath the sand, hunting for prey by night.
A photo of a striped pyjama squid. Its skin has a pattern of white and maroon stripes.

ALT A photo of a striped pyjama squid. Its skin has a pattern of white and maroon stripes.

8
Did you know a bird in Australia can sound like a chainsaw? About 80% of the superb lyrebird's song is copied from what it hears, and that can include chainsaws, car engines and dogs barking. It stitches them all into one long medley.
A superb lyrebird, a dark grey-brown bird with a long tail, walking through dry leaves and twigs on an Australian forest floor.

ALT A superb lyrebird, a dark grey-brown bird with a long tail, walking through dry leaves and twigs on an Australian forest floor.

2
1
1
19
Bonus: males sing and dance on little mounds they scrape up on the forest floor, with that huge tail fanned over their head.
4
Source: Australian Museum: Superb Lyrebird australian.museum/learn/anim…

Superb Lyrebird

The Superb Lyrebird looks like a large brown pheasant.

australian.museum
9
The scale really is epic. JUNO's main detector is an acrylic sphere 35.4 m across, holding 20,000 tonnes of liquid scintillator about 700 m underground, watched by around 17,600 big photomultiplier tubes.
New Scientist
@newscientistOct 20
One of the deepest mysteries in particle physics is how much neutrinos weigh and where their mass comes from. Now, an underground detector of truly epic scale in China is on the cusp of giving us an answer – and kicking off a new era of physics.
10
Did you know a day on Venus is longer than its year? It takes 243 Earth days to spin once but only 225 to go around the Sun. So you'd have a birthday before you got through a single day.
Venus in true colour, a pale cream-yellow globe wrapped in thick clouds.

ALT Venus in true colour, a pale cream-yellow globe wrapped in thick clouds.

2
1
2
24
Bonus: Venus also spins backward compared to Earth, so the Sun rises in the west there.
5
Source: NASA Science: Venus Facts science.nasa.gov/venus/facts…

Venus: Facts - NASA Science

Venus is the second planet from the Sun, and Earth's closest planetary neighbor. It's the hottest planet in our solar system.

science.nasa.gov
13
On this day in 1910, Titanic's big sister was launched in Belfast, and she'd go on to sink a U-boat. Olympic sailed for 24 years, earned the nickname "Old Reliable" as a WWI troopship, and in 1918 rammed and sank the German sub U-103 in the English Channel. #OnThisDay
Black-and-white photo of the hull of RMS Olympic sliding down the slipway at its launch in Belfast, 20 October 1910

ALT Black-and-white photo of the hull of RMS Olympic sliding down the slipway at its launch in Belfast, 20 October 1910

1
1
2
88
HiPOD: In Search Of...Wind Streaks A key feature of wind streaks is their high rate of erosion. Dark wind streaks erode a few centimeters a year. The proposed area appears to be a dark wind streak and is rapidly changing. uahirise.org/hipod/ESP_07735… #Mars #NASA
3
16
1
56
2,081
You can’t see dark matter in this image of the Coma Cluster, but you can see its effect on the thousands of galaxies present. Their motions are being held in check by an unseen gravitational force. #DarkMatterMonth 📷: CTIO/NOIRLab/DOE/NSF/AURA/D. de Martin & M. Zamani
2
15
39
890
European Space Agency: Euclid Discovers New Comet esa.int/Science_Exploration/…

Euclid discovers new comet

The European Space Agency’s Euclid space telescope has discovered its first previously unknown comet, in images taken between 16 and 24 September 2026.

esa.int
2
1
13
482
Load more