Space Facts Flashcard Deck

One hour on Earth is 0.0026 seconds in space. Thus, upon calculation we find that one hour on Earth is equivalent to seven years in space. Einstein's theory of Special Relativity stands as a explanation to this calculation.

Outer space is not completely empty—it is a hard vacuum containing a low density of particles, predominantly a plasma of hydrogen and helium, as well as electromagnetic radiation, magnetic fields, neutrinos, dust, and cosmic rays.

About 93 billion light-years. The proper distance—the distance as would be measured at a specific time, including the present—between Earth and the edge of the observable universe is 46 billion light-years (14 billion parsecs), making the diameter of the observable universe about 93 billion light-years (28 billion parsecs).

It extends about 20 miles (32 kilometers) above the Earth. Floating around the atmosphere is a mixture of molecules - tiny bits of air so small you take in billions of them every time you breathe.

Edwin Hubble: The man who discovered the Cosmos.

In space, there is no air or water, so the only way to lose heat is by radiation, where your warm and wiggly atoms release energy directly into space. This is a slow process, so you'd die of oxygen deprivation long before you'd notice the cold!

Scientists have recently observed for the first time that, on an epigenetic level, astronauts age more slowly during long-term simulated space travel than they would have if their feet had been planted on Planet Earth.

The first planet they land on is close to a supermassive black hole, dubbed Gargantuan, whose gravitational pull causes massive waves on the planet that toss their spacecraft about. Its proximity to the black hole also causes an extreme time dilation, where one hour on the distant planet equals 7 years on Earth.

But how does it work? Astronomers already use clocks to navigate in space. They send a signal to the spacecraft, which sends it back to Earth. The time of that round trip tells scientists the spacecraft's distance from Earth.

Outer space is a vacuum. You cannot breathe in a vacuum because there's literally no air to breathe, and if you tried, you'd be dead in about four minutes. Also, because space is extremely cold, your eyeballs could freeze solid, and even if you somehow survived, you'd be blind.

When we think of 'nothing,' we typically think of a space with nothing in it. A space that has zero particles, no particle at every place where a particle could be. Physicists call this the 'vacuum state,' and thanks to quantum mechanics, it has some weird properties.

On Earth, humans have oxygen to breathe. But there's very little oxygen to breathe in space. Space is actually a kind of vacuum, which means there isn't a whole lot of matter, or stuff, out there between the planets and the stars.

In fact, a small amount of gravity can be found everywhere in space. Gravity is what holds the moon in orbit around Earth. Gravity causes Earth to orbit the sun.

No, you cannot hear any sounds in near-empty regions of space. Sound travels through the vibration of atoms and molecules in a medium (such as air or water). In space, where there is no air, sound has no way to travel.

By definition, a vacuum is devoid of matter. Space is almost an absolute vacuum, not because of suction but because it's nearly empty.

13.77 billion years old. The universe is (nearly) 14 billion years old, astronomers confirm. With looming discrepancies about the true age of the universe, scientists have taken a fresh look at the observable (expanding) universe and have estimated that it is 13.77 billion years old (plus or minus 40 million years).

Around 13.8 billion years ago, all the matter in the Universe emerged from a single, minute point, or singularity, in a violent burst. This expanded at an astonishingly high rate and temperature, doubling in size every 10-34 seconds, creating space as it rapidly inflated.

Light-year is the distance light travels in one year. Light zips through interstellar space at 186,000 miles (300,000 kilometers) per second and 5.88 trillion miles (9.46 trillion kilometers) per year.

Trillions of years in the future, long after Earth is destroyed, the universe will drift apart until galaxy and star formation ceases. Slowly, stars will fizzle out, turning night skies black. All lingering matter will be gobbled up by black holes until there's nothing left.

Astronomers estimate that the sun has about 7 billion to 8 billion years left before it sputters out and dies. One way or another, humanity may well be long gone by then.

If we define 'universe' as 'all there is' or 'all that exists,' then obviously, by definition, there can be only one universe. But if we define 'universe' as 'all we can ever see' (no matter how large our telescopes) or 'space-time regions that expand together,' then many universes may indeed exist.