Almost everyone has gazed up at the night sky and marveled at the vastness of space, pondering the mysteries of that last frontier. But movies, TV shows, and books have given rise to some distorted assumptions about the universe around us. So, let’s use science to clear up that misthinking and address ten of the most common myths and misconceptions about our universe.
Related: The 10 Strangest Stars We’ve Discovered
10 Many of the stars we see at night are dead and no longer exist.
Light from a distant or dying sun takes a long time to reach us on Earth. Therefore, many of the 6,000 stars we see at night must be dead, burned out, and emitting no more light. Good?
Well not really. Those 6,000 visible stars are likely to continue to shine brightly and function well. The stars we can see from Earth are less than 1,000 light-years from us, which is actually pretty close to stars. Therefore, it is highly unlikely that any star we see died in the time it takes for its light (traveling at 186,000 miles/second or 300,000 km/second) to reach us.
9 the universe is infinite
The universe is big, of that there is no doubt, but in reality it is finite. It has an end.
Our galaxy alone, the Milky Way, has more than 200 billion stars. And there are an estimated two trillion galaxies in the universe. But it is still measurable. The outer edges of the universe are 47 billion light-years from us in all directions, that’s the radius. And the distance across (the diameter) from end to end is 94 billion light years.
A more mind-boggling consideration is: what lies beyond those planets and stars at the outer edge of the universe?
8 Black holes are like giant vacuum cleaners: they suck everything up.
Unlike what we’ve seen in the movies, black holes aren’t menacing cosmic tornadoes, sucking up everything in their galactic path. Black holes also do not search for planets to consume in order to survive, thrive, and grow.
Black holes occur when massive stars run out of fuel and begin to die and collapse. During that collapse, the star becomes denser and denser, creating ever-increasing gravity which, in turn, begins to pull on nearby objects (and even light!). And yes, that gravity could affect planets, moons, and other stars, pulling them toward the event horizon, the black hole’s outer opening. But the gravity of that black hole is just regular gravity, only there’s more to it. For example, if a star 10 times the size of our sun dies, collapses, and creates a black hole, the gravity of that black hole would be the same as the mass of a star 10 times the size of our sun.
7 Dark matter is evil and destructive
Dark matter has been used as a plot element in many movies and television shows.the expansion, star trek, futurama, X-filesand even Scooby Doo, to name a few. But is he really sinister, nefarious and evil?
Of course not.
Dark matter is completely invisible and has never been seen or detected, but it makes up 27% of the matter in the universe. It’s basically what’s in the gaps between suns and galaxies. Most scientists believe that this invisible material is made up of WIMPS, weakly interacting massive particles, and those particles have a much denser mass than a proton. But they react so weakly with other matter that they are hard to detect (ie “dark”).
6 Earth-like planets are rare
Proxima Centauri b is the closest Earth-like (and possibly habitable) planet to us, at just four light-years away. And using the technology we have now, it would still take over 60,000 years to travel there.
But let’s not confuse the proximity of another habitable planet with the possible existence of other Earth-like planets. Astronomers estimate that there are 300 million to 6 billion potential Earths in the Milky Way galaxy alone. And with 10 trillion galaxies in the universe, there could be 76,000,000,000,000,000,000,000 stars similar to our sun, with habitable planets in orbit.
5 Once we perfect the speed of light travel, we will be able to travel through the galaxies
Warp speed, hyperdrives, and other futuristic technologies are always effective in fiction for traveling from planet to planet and galaxy to galaxy. But in the real world, traveling at the speed of light, or even near the speed of light, is impossible.
Einstein told us in his Theory of Relativity that as objects increase in speed, they gain mass, they get heavier. So any object accelerating to even close to the speed of light would start to have infinite mass or energy. And that just can’t happen. A photon, which has no mass/weight, has been accelerated in the laboratory to 99% of the speed of light, but the energy required to propel even one gram of anything would require an infinite amount of energy.
Simply put, nothing with a mass can reach the speed of light.
4 The Big Bang was an explosion
The universe and everything in it began with a giant bang. I mean, it’s right there in the name: The BIG BANG Theory. But cosmologists are always trying to figure that out.
Scientists have accepted the theory that the universe began 13.8 billion years ago when an infinitesimally small ball of dense matter exploded. But did something really go off and blow up?
The consensus is that it all started with rapid expansion, not the detonation of a bomb-like explosion. And that rapid expansion (faster than the speed of light) was of space, not of objects in our universe. Everything is still in the same position now as it was 13.8 billion years ago, but it is the space between those objects that is growing. This explains why there is no vacuum at the center of our universe, which we would expect to find with an explosion (a burst) when everything shoots out from a central point.
3 Aliens could come to Earth
That sounds plausible, especially considering the thousands of UFO sightings in North America each year. And if only a fraction of those encounters were genuine, one might reasonably assume that alien visitors to Earth are a possibility.
But let’s look at those massive numbers again.
With 76,000,000,000,000,000,000,000 stars in the universe that have habitable planets orbiting them, there is absolutely no doubt that there is other life out there, some developing, some intelligent, and perhaps some technologically advanced. The question is: could these advanced beings travel to earth?
Our galactic neighborhood alone, the Milky Way, is 100,000 light-years across, and even aliens have to grapple with the logistical problems of space travel: food, fuel, radiation, etc. Right now, the fastest man-made object in space is the Voyager spacecraft, traveling at a breakneck speed of 11 miles per second. But even at that rate, Voyager wouldn’t reach the nearest star for another 73,000 years. Given all the dangers along the way, how could any being survive a journey that could take millions of years?
It’s like Neil DeGrasse Tyson said: “Scientifically, we have a rule: you want to be alive at the end of your experiment, not dead.”
So yes, there is life out there. But it doesn’t come here.
2 In space, no one can hear you scream
As the saying goes, in space no one can hear you scream. And since space is a vacuum, with no substance for sound waves to travel through, that statement makes sense: a scream shouldn’t even be able to escape your lips.
However, NASA researchers now say it depends on where you are in space. Listening to an immense (gas-rich) black hole near the Perseus Cluster, a galaxy 250 million light-years away, scientists heard all sorts of eerie sounds. So if you want to scream in an area of space with dense gases, plasma and other particles, go ahead, you won’t lose your breath.
1 Our sun is a giant fireball
Well, actually, it’s more like an endless series of hydrogen bomb explosions.
Hydrogen atoms in the sun’s core collide with helium atoms and fuse. That fusion, or that nuclear reaction, releases huge amounts of energy, just like a nuclear power plant. And those reactions have been feeding the sun for four billion years. Fortunately for Earth, the sun’s density and gravity are so great that it holds everything together and prevents it from exploding.
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