“We See It As It Existed 2.5 Million Years Ago” – Astronomers And Cosmologists Are Blowing People’s Minds With Their Fave Space Facts
by Benjamin Dzialdowski · BuzzFeedSpace is pretty unfathomable and, let's face it, terrifying; but it is also absolutely fascinating. So, when MapWise3890 asked astronomers and cosmologists to share the space facts that are inconceivable to us normal folks, we had to take a share them along with you.
1. "Not the entire universe, but when atoms in the core of the Sun fuse and release energy, that energy bounces from atom to atom for hundreds of thousands of years until it reaches the surface, then zips into space."
"And it is this outward flow of energy that keeps the star from imploding. So when the fuel runs out, thats exactly what happens."
2. "Pulsars are all unique in how they pulse, and at least in theory could be used like a galactic GPS."
Editor's note: Pulsars are rapidly spinning neutron stars, extremely dense stars composed almost entirely of neutrons and having a diameter of only 20 km (12 miles) or less.
3. "An ancient Greek scientist, Eratosthenes, calculated the size of the Earth using shadows. He was less than 1% off."
4. "The Pleiades were not formed when the dinosaurs first walked the Earth. They are also younger than sharks (as a group)."
Editor's note: According to the Royal Museums Greenwhich, The Pleiades were "one of the most easily recognisable star clusters in the night sky is the Pleiades, also known as the ‘Seven Sisters’ or M45."
5. "Let's say you have a spacecraft that gets you to 99.99999999% of the speed of light. You could make it one way to the Andromeda Galaxy in your lifetime, but if you wanted to go back to Earth, about five million years would have passed."
6. "The fact that the Sun and the Moon appear roughly the same size in the sky is a complete cosmic coincidence. The Sun is 400x larger than the Moon in diameter, but it’s also 400x further away. We don’t know of any other Sun-Planet-Moon system that has this same 1:1 ratio. Experiencing a total solar eclipse — where a moon is just large enough to cover the star’s photosphere, but not so big that it blocks the view of the surrounding corona — is a Universally unique experience."
Editor's note: While we don't know of any ratio like this, we can't say it's 100% unique.
7. "This is my favorite existential crisis fact I tell people when I do public outreach with my telescope. Our nearest neighbour is the Andromeda Galaxy which is 2.5 million light years away. That means we see it as it existed 2.5 million years ago. If there were a sentient life form on a planet in Andromeda looking at us with a telescope powerful enough to see the surface of Earth, they would see humanity as homo habilis just starting to leave the caves 2.5 million years ago."
8. "The sheer scale of it."
"100-400 billion stars in our galaxy alone. Estimated upwards of 2 trillion galaxies in the observable universe, which for all we know might only be a tiny fraction.
So that’s roughly 800,000,000,000,000,000,000,000 stars, each likely with planets, moons, and entire systems.
To quote Carl Sagan, we really are just a mote of dust suspended in a sunbeam."
9. "The interior of the sun is enormously hot and high pressure. The massive pressure rattles hydrogen atoms so hard that they can bump into each other and fuse into helium, releasing a bit of energy."
"The sun produces so ridiculously much energy that even here on earth 150 million km away it can be blazingly hot in the midday sun.
But if you took 1m3 of the sun's core, and compared it to 1m3 of human body, our human bodies actually output more energy per volume. It's just that the sun is unimaginably large."
10. "There are more stars in the observable universe than there have been seconds since the big bang."
11. "Our galaxy, the Milky Way, and our nearest sizable neighbour, the Andromeda Galaxy, are on a collision course, and they will eventually merge and form a new galaxy. But the space between individual stars is so vast that the expected number of collisions between a Milky Way star and an Andromeda star in the process is zero."
Editor's note: Data from Hubble and the European Space Agency’s Gaia space telescope suggests there is less certainty about the collision of the two galaxies, with there being roughly a 50% chance of the merge in the next 10 billion years.
H/T to MapWise3890 and r/AskReddit for having the discussion!
What's your favourite space fact? Let us know in the comments below!
Additional thumbnail credits: Sony Pictures Releasing International, Alex-mit / Getty Images/iStockphoto