Space
Beyond Earth, everyday yardsticks fail — from the length of a day to the size of a star.
32 articles
Can you see the Great Wall of China from space?
“The only man-made structure visible from space.” Nearly everyone has heard it. So what do the people who have actually been to space have to say?
How much space junk is there?
Roughly 70 years after humanity first reached space, the things we’ve “dropped” keep piling up around Earth, mostly too small to see.
Is there really a planet where a day is longer than a year?
Right next door to Earth is a planet where our sense of time is turned upside down. There, the Sun rises in the west.
What does space smell like?
With no air in space, there is nothing to sniff. Yet astronauts describe “the smell of space” in remarkably similar terms.
Is the Moon really drifting away from Earth?
At about the pace your fingernails grow, the Moon is slowly taking its leave. And the price Earth pays for it turns out to be time itself.
What is the biggest star in the universe?
Put this star where the Sun is, and it might reach as far as Saturn’s orbit. But the title of biggest star has changed hands surprisingly often.
What is the coldest place in the universe?
Empty space is already bitterly cold. Yet astronomers found a place that dips below even that cosmic floor.
Will the Sun burn out someday?
Even the Sun that rises faithfully every morning has a lifespan. Follow the life story of a star, and the Sun’s surprising “final days” come into view.
Would Saturn float in water?
Drop the solar system’s second-largest planet into a giant bathtub: would it sink or bob? The more you think about it, the more fun the thought experiment gets.
What exactly is a shooting star?
A flash across the night sky, the kind people make wishes on. What causes it turns out to be nothing like the stars shining overhead—and astonishingly small.
How long does sunlight take to reach Earth?
The Sun you see overhead isn’t the Sun as it is right now. Even for the fastest thing in the universe, the journey is a long one.
Why is the night sky dark?
When the Sun goes down, it gets dark. That obvious fact turns out to be a puzzle that troubled astronomers for centuries.
Why do stars twinkle?
Just as the nursery rhyme says, the stars in the night sky twinkle. Yet in that same sky, some lights barely twinkle at all.
Why do comet tails point away from the Sun?
A long tail sweeping across the night sky like a broom. It is tempting to think a comet trails its tail behind it as it flies, but that isn’t always the case.
Do astronauts get taller in space?
Is it really true that going to space makes you taller? A Japanese astronaut’s “9-centimeter incident” offers a good place to start.
How many times a day does the International Space Station circle Earth?
A huge laboratory flies 400 kilometers over our heads. For the astronauts who live there, a “day” runs to a rhythm completely unlike ours on the ground.
Why is the Milky Way called a “river” in Japan?
Looking up at the same band of light, some peoples pictured a river and others spilled milk. The names we give the night sky reflect the stories of those who gaze at it.
Why can’t we see the far side of the Moon?
For thousands of years, humanity has looked up at the same lunar markings. There’s a good reason the Moon’s other half stays hidden.
Why is Pluto no longer a planet?
Generations of students learned nine planets, ending with Pluto. Why did a world that had been a planet for 76 years suddenly lose its place one day?
What is the tallest mountain in the solar system?
Mount Everest is the roof of our world, but across the solar system there are peaks that dwarf it. Other worlds hold mountains on a scale that is hard to imagine.
Is there sound in space?
In sci-fi movies, spaceships explode with a deafening roar. Is real space silent? Mostly, yet in some places an unimaginably deep “song” rings out.
What is the nearest star to the Sun?
Of all the countless stars in the night sky, which one is our closest neighbor? Surprisingly, it is a star you cannot see with the naked eye.
What happens if you fall into a black hole?
Imagine leaping feet first into an object not even light can escape. What you experience and what a friend watching from afar sees would be completely different.
Is Jupiter’s Great Red Spot shrinking?
A giant red swirl floats on the face of Jupiter. This storm has raged for nearly two centuries, and lately it has been changing in a way no one can miss.
How long will footprints last on the Moon?
More than half a century ago, Apollo astronauts left footprints on the Moon. They are often said to last for millions of years, but a spacecraft that has kept watch over the lunar surface revealed something unexpected.
Will Polaris always be the North Star?
As every other star wheels across the sky, one stays put in the north. This guide for travelers has a term of office, too.
Why is Uranus tipped on its side?
Every planet in the solar system spins like a top as it circles the Sun. Every planet, that is, except one, which rolls along lying flat on its side.
What happens if you cry in space?
When we’re sad or happy, tears roll down our cheeks. But if you cry aboard a spacecraft, where there is no up or down, where do the tears go?
Does the Moon have earthquakes?
No air, no oceans, and volcanoes that seem to have gone quiet long ago. Yet the ground on the Moon turned out to be far from still.
Are sunsets on Mars blue?
Mars is known as the Red Planet. When a rover photographed the Sun setting in its sky in color, the scene it captured looked nothing like a sunset on Earth.
How did the Moon form?
It is the most familiar object in the night sky, yet scientists are still debating how it came to be. The clues came from rocks that astronauts brought home.
What is the largest moon in the solar system?
Our Moon looks impressively large in the night sky. But across the whole solar system, where does the biggest moon of all circle its planet?