Almost everyone stared up at the night sky and marveled at the vastness of space, wondering about the mysteries of this final frontier. But movies, TV shows and books have led to distorted assumptions about the universe around us. So let’s use science to clarify this misconception and address ten of the most common myths and misconceptions about our universe.
Related: 10 Weirdest Stars We’ve Discovered
ten Many 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, burnt out, and no longer emitting light. Right?
Well not really. These 6,000 visible stars are probably all still bright and doing very well. The stars we can see from Earth are all within 1,000 light-years of us, which is actually quite close for stars. It is therefore highly unlikely that any star we see died in the time it took for its light (travelling at 186,000 miles/second or 300,000 km/second) to reach us.
9 The universe is infinite
The universe is big, there’s no doubt about it, but it’s actually finite. It has an end.
Our galaxy alone, the Milky Way, has over 200 billion stars. And there are about 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 (diameter) from one end to the other is 94 billion light years.
A more mind-blowing consideration is this: what is beyond those planets and stars on the outskirts of the universe?
8 Black holes are like giant vacuum cleaners, they suck up everything
Unlike what we’ve seen in the movies, black holes aren’t menacing cosmic tornadoes, sucking up everything in their galactic path. Nor do black holes hunt 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 this collapse, the star becomes increasingly dense, creating an ever-increasing gravity, which, in turn, begins to exert an attraction on nearby objects (and even light!). And, yes, this gravity could affect planets, moons, and other stars, pulling them into the event horizon, the black hole’s outer opening. But the gravity of this black hole is just normal gravity – there’s just more of it. For example, if a star 10 times the size of our sun died, collapsed, and created 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.
seven Dark matter is evil and destructive
Dark matter has been used as a plot device in many movies and TV shows –The extent, star trek, Futurama, X-Filesand even scooby-doo, to name a few. But is it really sinister, nefarious and diabolical?
Of course not.
Dark matter is totally invisible, and it has never been seen or detected, yet it represents 27% of the matter in the universe. It’s basically the stuff in the voids between suns and galaxies. Most scientists believe that this invisible material is made up of WIMPS – weakly interacting massive particles – and that these particles have a much denser mass than a proton. But they react so weakly with other materials that they are difficult to detect (ie “dark”).
6 Earth-like planets are rare
Proxima Centauri b is the closest Earth-like (and possibly habitable) planet to us, a mere four light-years away. And using the technology we have now, it would take another 60,000+ years to get 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 between 300 million and 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 orbiting them.
5 Once we perfect travel at the speed of light, we can travel the galaxies
Warp speed, hyperdrives, and other futuristic technologies are still effective in fiction for jumping from planet to planet and galaxy to galaxy. But in the real world, traveling at the speed of light, or even traveling at the speed of light, is an impossibility.
Einstein told us in his theory of relativity that as objects increase in speed, they gain mass – become heavier. So any object accelerating even at near light speed 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 lab to 99% of the speed of light, but the energy to propel even a gram of anything would take an infinite amount of energy.
Ultimately, nothing with mass can ever reach the speed of light.
4 The Big Bang was an explosion
The universe and everything in it started with a giant explosion. I mean, it’s right there in the name – The BIG BANG Theory. But cosmologists are still trying to clarify this.
Scientists have accepted the theory that the universe began 13.8 billion years ago when an infinitely small dense ball of matter exploded. But did something really explode?
The consensus is that it all started with a rapid expansion, not an explosion-like bomb blast. And this rapid expansion (faster than the speed of light) was about space, not objects in our universe. Everything is still in the same position as it was 13.8 billion years ago, but it is the space between these 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 bang) when everything is expelled from a central point.
3 Aliens could come to Earth
This seems plausible, especially given the thousands of UFO sightings in North America each year. And if only a fraction of these encounters were genuine, one would reasonably assume that extraterrestrial visitors to Earth are a possibility.
But let’s go back to those huge numbers.
With 76,000,000,000,000,000,000,000 stars in the universe having habitable planets orbiting them, there is no doubt that there are other forms of life out there, some in development, others smart and maybe some technologically advanced ones. The question is: could these advanced beings travel on Earth?
Our galactic neighborhood alone, the Milky Way, is 100,000 light-years across, and even aliens have to grapple with the logistical issues of space travel – food, fuel, radiation, etc. Currently, the fastest man-made object in space is the Voyager spacecraft, traveling at a blistering 11 miles per second. But even at this rate, Voyager won’t reach the nearest star for 73,000 years. Given all the perils along the way, how could any being imagine surviving 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 experience, not dead.”
So, yes, there is life 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 through which sound waves can travel, this statement makes sense: a scream shouldn’t even be able to come out of your lips.
However, NASA researchers now say it depends on where you are in space. Listening to a huge (gas-rich) black hole near the Perseus Cluster, a galaxy 250 million light-years away, scientists heard all kinds of strange sounds. So if you want to scream in an area of space with dense gases, plasma, and other particles, go for it, you won’t lose your breath.
1 Our sun is a giant ball of fire
Well, actually, it’s more like an endless series of hydrogen bomb explosions.
Hydrogen atoms in the core of the sun turn into helium atoms and fuse together. This fusion – or nuclear reaction – releases large amounts of energy, much like a nuclear power plant. And these reactions have been powering the sun for four billion years. Luckily for Earth, the sun’s density and gravity are so great that it holds everything together and keeps itself from exploding.
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