Space & Cosmos
How do astronauts sleep in space?
How do astronauts sleep in space? Zipped in wall-strapped bags through 16 daily sunrises, with masks, earplugs, and, a 2014 Lancet study found, sleep meds.
Space & Cosmos
Black holes, stars, planets, and the scale of everything.
Space & Cosmos
Can you see the Milky Way with the naked eye?
Can you see the Milky Way with the naked eye? Yes, under dark skies, but light pollution hides it from ~80% of North Americans. Here's how and where to look.
Space & Cosmos
Can you see the Moon during the day? Yes, almost daily
Can you see the Moon during the day? Yes, on most days of the month. It's bright enough to show against the blue when it's clear of the Sun's glare.
Space & Cosmos
How Many Moons Does Jupiter Have? The Count Keeps Climbing
How many moons does Jupiter have? NASA recognizes 101 officially, and the latest catalog lists 115 as of April 2026. Here is why the number keeps rising.
Space & Cosmos
What would happen if you fell into a black hole?
In an idealized quiet system, a small black hole can shred you before the horizon, while a supermassive one may let you cross before tides become lethal.
Space & Cosmos
What is the temperature on the moon? From boiling to deep freeze
What is the temperature on the moon? It swings from about 120 C in daylight to -130 C at night, with polar craters near -240 C, because the Moon has no atmosphere.
Space & Cosmos
Why do we have seasons? It's the tilt, not the distance
Why do we have seasons? Earth's axis is tilted about 23.5 degrees, so each hemisphere leans toward the Sun for half the year. It's the tilt, not the distance.
Space & Cosmos
How Old Is the Universe? 13.8 Billion Years, and How We Know
How old is the universe? About 13.8 billion years, measured from the oldest light in the sky and the rate at which the cosmos is still expanding.
Space & Cosmos
Why is Venus the hottest planet? Not the one closest to the Sun
Why is Venus the hottest planet when Mercury sits closer to the Sun? A runaway greenhouse effect and thick carbon dioxide trap the heat with nowhere to go.
Space & Cosmos
What would happen if the Sun disappeared? Minute by minute
What would happen if the Sun disappeared? For 8 minutes, nothing. Then darkness, Earth flung into space, and a slow freeze. Here is the full timeline.
Space & Cosmos
How big is the sun compared to earth? 109 across, a million inside
How big is the sun compared to earth? About 109 times wider, big enough to swallow 1.3 million Earths, and holding 99.8% of all the mass in the solar system.
Space & Cosmos
How do astronauts poop in space? Very carefully, with a lot of airflow
How do astronauts poop in space? With airflow, not gravity. NASA's toilet suctions waste away, recycles urine into drinking water, and burns the rest up.
Space & Cosmos
How long would it take to get to the moon? From 1.3 seconds to over a year
How long would it take to get to the moon? About 3 days like Apollo, 8.5 hours at the fastest flyby, or 14 months by ion engine. It all depends on how you travel.
Space & Cosmos
What Is a Shooting Star? Not a Star at All, Just a Speck Burning Up
What is a shooting star? Not a star at all. It's a meteoroid, often a grain of dust or a pebble, burning up about 75 to 120 km overhead as it hits the air.
Space & Cosmos
Why is the moon moving away from earth? Blame the tides
Why is the moon moving away from earth? Tidal friction nudges it 3.8 cm farther each year, the speed your fingernails grow, while slowly stretching out our days.
Space & Cosmos
What are Saturn's rings made of? Mostly ice, and they are vanishing
What are Saturn's rings made of? Over 95 percent water ice, from dust grains to house-sized boulders, and they are young, thin, and slowly raining away.
Space & Cosmos
How Loud Would the Sun Be If We Could Hear It? Around 100 dB
How loud would the sun be if we could hear it? Estimates put it near 100 dB at Earth, about a rock concert, but space is a vacuum so the sound never arrives.
Space & Cosmos
What Is a White Hole? Real Math That Nature Never Built
What is a white hole? It is a black hole with time reversed: a region nothing can enter. Real math, badly unstable, and never once seen in the sky.
Space & Cosmos
Is the Universe Infinite? Space Is Flat, and That Settles Nothing
Is the universe infinite? Space measures flat to within a fraction of a percent, which permits an endless cosmos but cannot prove one. Here's why.
Space & Cosmos
Why is Mars red? It is rusting, and that is a clue to its watery past
Why is Mars red? The planet is coated in iron oxide dust, the same stuff as rust. A 2025 study points to a water-bearing mineral, hinting Mars was once wet.
Space & Cosmos
How Big Is the Biggest Star Compared to the Sun? Up to 2,000+ Times Wider
How big is the biggest star compared to the sun? The largest known stars are roughly 1,500 to 2,100+ times the Sun's radius, big enough to swallow the inner planets.
Space & Cosmos
What Would Happen If the Moon Crashed Into Earth? It Would Shatter First
What would happen if the moon crashed into earth? It would break apart into a ring long before impact, when it crossed Earth's Roche limit. And it can't happen.
Space & Cosmos
How Long Would It Take to Drive to the Sun? About 177 Years
How long would it take to drive to the sun? At a steady 60 mph nonstop, about 177 years. Light makes the same trip in 8 minutes, and one NASA probe in 9 days.
Space & Cosmos
What Is on the Other Side of a Black Hole? Honestly, Nobody Knows
What is on the other side of a black hole? Likely a singularity we can never see, while white holes and wormholes stay math, not proof. Here is the honest answer.
Space & Cosmos
How Many Earths Can Fit in the Sun? About 1.3 Million
How many earths can fit in the sun? About 1.3 million by volume, or roughly 960,000 packed as solid spheres, with 109 lined up across its face.
Space & Cosmos
How cold is space? Colder than almost anywhere, but not how you think
How cold is space? Empty space sits at about -270C, just above absolute zero. But a vacuum has no real temperature, and you would overheat before you froze.
Space & Cosmos
What does space smell like? Astronauts say seared steak
What does space smell like? Astronauts describe seared steak, hot metal, and gunpowder clinging to suits after spacewalks. Here is the chemistry behind it.
Space & Cosmos
Why is Pluto not a planet? The vote that demoted a world
Why is Pluto not a planet? In 2006 astronomers voted it a dwarf planet for failing one rule: it never cleared its orbit. The story, and the man who killed it.
Space & Cosmos
Where Does Gold Come From? The Cosmic Catastrophe Behind Every Wedding Ring
Where does gold come from? The gold in your jewelry was forged in a neutron star collision billions of years ago. Here's the wild physics behind it.
Space & Cosmos
How Do Black Holes Die? The Slow Fade of the Darkest Things
How do black holes die? Through Hawking radiation, they slowly evaporate over almost unimaginable spans of time. Here's how the universe's darkest objects end.
Space & Cosmos
How Big Is the Universe? (And Does It Have an Edge?)
How big is the universe? The observable universe spans 93 billion light-years, but the whole thing may be infinite. Here's what 'size' even means in space.
Space & Cosmos
What Happens When the Sun Dies?
What happens when the sun dies? In 5 billion years it swells into a red giant, swallows the inner planets, and fades to a white dwarf. Here's the timeline.
Space & Cosmos
Why Do Stars Twinkle but Planets Don't?
Why do stars twinkle while planets shine steadily? The answer is our turbulent atmosphere bending starlight, and a surprising trick of distance and size.