What did Galileo discover with his telescope?
In 1610, Galileo Galilei used his improved telescope to discover four of Jupiter's moons, which supported the idea that not everything orbits Earth.
Why was Galileo put on trial?
In 1633, Galileo was put on trial by the Catholic Church for supporting the idea that Earth orbits the Sun, and he spent the rest of his life under house arrest.
What did Galileo observe about Venus?
Galileo observed that Venus has phases like the Moon, evidence that it orbits the Sun.
How many sunrises do astronauts on the ISS see each day?
The International Space Station orbits Earth about every 90 minutes, so astronauts see about 16 sunrises a day.
Is the Moon moving away from Earth?
The Moon is drifting away from Earth by about 3.8 centimeters a year.
Why do we always see the same side of the Moon?
The Moon is tidally locked to Earth, which means it always shows us the same side.
Is a day on Mercury longer than its year?
From sunrise to sunrise, one day on Mercury lasts about 176 Earth days, twice as long as its 88-day year.
What is BepiColombo?
BepiColombo, a joint European and Japanese mission, is scheduled to enter orbit around Mercury in late 2026.
How did Mercury help prove relativity?
Mercury's orbit helped confirm Einstein's theory of general relativity.
Is a day on Venus longer than its year?
A day on Venus, about 243 Earth days, is longer than its year of about 225 Earth days.
How long is a year on Mars?
A year on Mars is about 687 Earth days.
What is unusual about Neptune's moon Triton?
Neptune's largest moon, Triton, orbits backward and will eventually be torn apart by Neptune's gravity.
When did Neptune complete its first orbit since its discovery?
A year on Neptune is about 165 Earth years, and in 2011 it completed its first orbit since being discovered.
Has Pluto completed an orbit since it was discovered?
Pluto takes about 248 Earth years to orbit the Sun, so it hasn't completed a full orbit since it was discovered.
Is Pluto ever closer than Neptune?
Pluto was closer to the Sun than Neptune from 1979 to 1999.
How long does it take the solar system to orbit the Milky Way?
Our solar system takes about 230 million years to orbit the center of the Milky Way.
Would Earth get sucked in if the Sun became a black hole?
If the Sun were replaced by a black hole of the same mass, Earth's orbit wouldn't change.