The Milky Way
Tonight, when the sun goes down, look up. Depending on how dark it is outside, you can probably see several thousand stars up there, all of which come from our own galaxy, the Milky Way. If you look a bit closer though, you might be able to spot one of only a few galaxies other than our own that is visible with the naked eye.
If this makes you feel small, it should, because scientists estimate that there are hundreds of billions more galaxies in the universe, none of which you can see without a telescope. Moreover, each one of these galaxies has billions of stars, which brings the estimated grand total number of stars in the universe to 10 billion trillion. That’s more stars than the number of grains of sand on the Earth.
All the stars, galaxies, and black holes in the universe only compose about 5% of its mass. As crazy as it sounds, the other 95% is unaccounted for. Scientists decided to label this mystery material “dark matter.” To this day, they are still not sure where or what it is.
The Alcoholic Space Cloud
For those of you considering opening your own pubs, there is probably no place better than Sagittarius B. Although it is 26,000 light years away, this interstellar cloud of gas and dust contains over a billion billion billion liters of vinyl alcohol. Okay, so it’s not really drinkable, but it’s a very important organic compound that is critical to the existence of life.
Nuking the Moon
In the late 1950′s, by way of something labeled Project A119, the United States decided it would be a good idea to launch a nuclear missile at the moon. Why? Evidently, they felt it would give them a leg up in the Space Race. Fortunately, however, the plan was never executed.
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The Ponzo Illusion
Have you ever noticed that when the moon is directly on the horizon, it appears to be a lot closer and larger? Known as the Ponzo illusion, your brain inflates the size of the moon to make it appear larger than it really is. Don’t believe it? Next time you’re looking at an oversized moon block everything else out with your hands and watch it shrink.
The Moon smells like gunpowder
Upon leaving the moon, astronauts on the Apollo missions described moon dust as smelling like gunpowder and feeling extremely soft. Scientists, however, are still not exactly sure why this is because the two have extremely different compositions with moon dust consisting mostly of small shards of silicone dioxide glass.
Biggest Diamond Ever
In 2004, scientists discovered the largest diamond ever. In fact, it’s a collapsed star. Measuring 4,000 km (2,485 miles) across and having a core composed of 10 billion trillion trillion carats, it’s roughly 50 light years from the Earth.
Venus’s day is longer than its year
Strangely enough, Venus completes an entire orbit around the sun before it manages to turn on its axis once. This means that its day is actually longer than its year.
As big as the planet Saturn is, if you were to put it in a glass of water, it would float. This is because its density is .687 grams per cm cubed, while water is the famous .998 g per cm cubed. Unfortunately, though, you would need a glass that is over 120,000 km (74,564 miles) in diameter to witness this.
Whenever two pieces of metal in outer space touch each other, they are more or less permanently stuck together. While welding usually requires heat, in this case, the vacuum of space does the trick, hence the name. You might think then, how do space shuttles accomplish anything out there? Well, typically, metals on Earth have a layer of oxidized material covering their surface that prevents this, so on shuttle missions, the risk of accidentally welding the shuttle to itself is negligible.
Earth has more than 1 moon
Okay, not really. They’re more like moon-wannabes, but scientists have discovered several asteroids that are more or less following the Earth as it moves around the sun.
Earth does, however, have over 8,000 objects orbiting around it. Most of these would be classified as “space junk” or debris left over from spacecraft and missions in the past.
Each year, scientists have determined that the moon moves about 3.8 cm further from the Earth. As a result, Earth’s spin has slowed by about .002 seconds every day over the course of the last century.
The Sun’s rays on your skin are 30,000 years old
While most of us know that the light hitting Earth took 8 minutes to cross the 93 million miles between our skin and the surface of the Sun, did you know that the energy in those rays started their life over 30,000 years ago deep within the core of the sun? They were formed by an intense fusion reaction and spent most of those thousands of years making their way to the Sun’s surface.
The Big Dipper is not a constellation
While it’s not our intention to burst your bubble, we thought we should inform you that it is actually an asterism. There are only 88 official constellations in the night sky, and everything else, including the Big Dipper, falls into this other category. It is, however, composed of the 7 brightest stars in the Great Bear (Ursa Major) constellation.
You are standing on a planet that is spinning about its axis while rotating around a star that is revolving around the center of a galaxy barreling through space. Sounds like enough to give you motion sickness, right? Well, before you take your Dramamine, let’s visit our next point.
Galileo’s Theory of Special Relativity
So, how do you know that the bus you are taking to work is in fact moving? What if you are sitting in the only motionless object in the known universe and everything else, including the road beneath your tires, is moving instead? Well, the truth is that there is no way to prove what is moving and what isn’t. It’s all relative to your frame of reference. To you, the person across the aisle is stationary because your frame of reference is the bus. To the person watching from the sidewalk, however, you are both speeding along at 60 mph (96.5 k/hr) through traffic because their frame of reference is the earth. Let’s take this a step further though as we move on to…
The Speed of Light
Going back to the bus example, if you were to shoot an arrow out the window at a target down the road in front of you, how fast would it be moving when it hit the bullseye? Well, essentially it would be going the speed of the bus – about 60 mph – plus however fast you shot the arrow. Now what if you shined a beam of light at it? Since the light travels at 186,000 miles per second, we would just add the 60 mph right? Wrong. Scientists found that no matter what, light travels the same speed. Which brings us to our next point…
The Universal Speed Limit
As a result of the aforementioned fact that light cannot exceed 186,000 miles per second, it would follow that nothing can, which is exactly why this has come to be known as the universal speed limit. This however, has some interesting consequences and leads directly into…
Einsteins Theory of Relativity
Without getting too complex, Einstein essentially came forward with the revolutionary idea that not only is motion relative, but time is too. In fact, they are linked together. The faster you move, the slower others will perceive that time has passed for you. While this was exactly the kind of nonsense scientists were trying to avoid, Einstein took it at face value and accepted the conclusion. Still don’t believe it? That’s why we’re moving on to…
Everything we just talked about is very relevant to modern technology. In fact, the clocks in onboard computers and navigation equipment have to take into account the effects of relativity. For example, if you measured the time that had elapsed on a fighter pilots wristwatch, you would find that it lagged behind your watch by several nanoseconds.
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Because the force of gravity increases near the surface of the Earth, so does your acceleration, meaning exactly what you’re thinking – time slows down. Once again, this is very relevant to modern day society because, at different altitudes, clocks tick at different “speeds.” Also, remember that since the earth is rotating, someone standing near the equator is moving faster than someone on the north pole. Once again, their clock is ticking slower.
If you have been keeping up so far, then this won’t be too much of a leap. The famous Twins Paradox states that if you put one twin on a spaceship that was moving near the speed of light through space and left the other on Earth, due to the effects of relativity, the twin in the spaceship would return to the planet significantly younger than his Earthbound sibling.
At one point, these intergalactic vacuum cleaners were actually supermassive stars. When one dies, it generally blows off its gaseous outer layers and the core collapses into an extremely small and dense sphere. Imagine, for example, trying to pick up a tennis ball containing the entire mass of the Sun. The immediate effect of this astronomically high density would be an insanely strong gravitational field. To break free from any gravitational field, you have to be traveling faster than something known as escape velocity. On Earth, spacecraft reach a speed of about 7 miles per second. On some collapsed stars, though, they would have to reach a speed faster than 186,000 miles per second which is more than the universal speed limit, meaning nothing – not even light – could escape.
Original PNG version: Stib at en.wikipedia, World line, CC BY-SA 3.0 , 9. pixabay (Public Domain), 10. Pixabay.com (Public Domain), 11. Pixabay.com (Public Domain), 12. The original uploader was Tomruen at English Wikipedia., Lunar perigee apogee, CC BY-SA 3.0 , 13. David.Shikomba, Space Junk, CC BY-SA 3.0 , 14. WikipediaCommons.com (Public Domain), 15. WikipediaCommons.com (Public Domain), 16. WikipediaCommons.com (Public Domain), 17. WikipediaCommons.com (Public Domain), 18. PublicDomainPictures.net (Public Domain), 19. Pixabay.com (Public Domain), 20. Pixabay.com (Public Domain), 21. WikipediaCommons.com (Public Domain), 22. WikipediaCommons.com (Public Domain), 23. ESA/Hubble, Collage of six cluster collisions with dark matter maps, CC BY 4.0 , 24. NASA Goddard Space Flight Center, Hubble Sees a Legion of Galaxies, CC BY 2.0, 25. Steve Jurvetson, Under the Milky Way, CC BY 2.0