If you shrank the solar system down to the size of a quarter, and shrank the entire Milky Way galaxy down at the same ratio, the Milky Way would be the size of the entire United States. It’s 100,000 lightyears wide.

Ink pens won’t work in space because there’s no gravity to pull the ink down to the nib. You can’t use pencils because even tiny pieces of loose graphite can screw up equipment. Astronauts have to use specially made pens.

If two pieces of the same type of metal touch in space, they will permanently bond. This is known as “cold welding” and it happens because the atoms of two pieces of metal have no way of knowing they are separate. This doesn’t happen on Earth because of the air and water found between the pieces.

It would take about 300,000 full moons to make the night as bright as the afternoon.

In China, the Milky Way is known as the “Silver River.”

Jupiter, the largest planet in the solar system, is composed of hydrogen and helium. These are the same elements that our Sun is made up of. However, Jupiter is not large enough to start nuclear fusion and generate its own energy. If it were around 80 times bigger, it would become a star with low mass.

Mars has the largest natural formations in the solar system: a mountain three times taller than Mount Everest, a canyon nearly seven times longer than the Grand Canyon, and a crater that is half of the entire span of the Amazon River.

Mercury has no atmosphere, which means there is no wind or weather.

Every major galaxy has a black hole at the center of it.

Enceladus, one of Saturn’s moons, is the most reflective body in the solar system. It’s completely iced over and reflects nearly 100% of the sunlight that hits it.

All planets in the solar system have been visited by unmanned spacecraft.

The moons of Uranus were named after characters created by Alexander Pope and William Shakespeare.

Astronauts can’t burp in space.

Astronauts walking on the moon sometimes sank up to six inches deep into soft dust with each step.

About 1.4 billion years ago, a day on Earth was just 18 hours 41 minutes long.

A single space suit costs about $12 million.

Uranus’ blue glow is due to the gases in its atmosphere. Uranus’ atmosphere is made up of hydrogen, helium and methane. The methane in Uranus’ upper atmosphere filters out all the red light from the Sun but reflects the Sun’s blue light back into space, giving it its blue appearance.

Neptune’s moon, Triton, orbits the planet backwards. Triton is the only large moon of any of the planets that does this.

In 2016, scientists detected a radio signal from a source 5 billion light-years away. This means that when the signal started its journey, Earth didn’t even exist.

The first-ever black hole photographed is 3 million times the size of Earth. The photo was released in April 2019 and shows a halo of dust and gas surrounding a black hole that is 310 million trillion miles from Earth.

The Hubble Space Telescope is one of the most productive scientific instruments ever built. Astronomers using Hubble data have published more than 15,000 scientific papers.