10 – Asteroid Impact
This one is pretty self-explanatory. A giant rock smashes into earth causing varying effects based on size. A small one wouldn’t end life on earth, but could certainly put an end to modern life in the unlucky country it landed in. If it struck water, the tsunamis would be devastating to all coasts. A medium sized strike would could cause a nuclear winter. This would eventually destroy a huge percentage of life and only the most hearty creatures would live due to starvation. A very large asteroid impact would could turn the crust of the earth into magma. All life dies. This is a complete global killer.
This one isn’t as deadly, as the effects are more long term but a large enough solar flare could destroy our ozone layer. A world without an ozone layer wouldn’t be a place where life could thrive. It would be unshielded against cosmic rays, suns dangerous UV rays etc. Most life that exists now would eventually die off due to exposure if the Earth didn’t have such a shield.
This might be the most interesting way for the world to end. Though, very unlikely. It is estimated that there are over a million black holes in our galaxy alone. Black holes are very tough to see for obvious reasons. Scientists use a few indirect methods of looking for them — the effect of gravity on nearby objects and gravitational lensing of stars as they pass in front of them. We would only likely have a couple months warning if one was passing through our solar system.
Though, rather then being gobbled up by the black hole, a more likely scenario is that its gravity would disrupt the orbit of the planets, asteroids and even Earth. Thus causing objects to collide with the Earth at a rate similar to when the Earth was formed.
7 – Supernovae
I’d place my money on this one as the odds are probably the highest for being Earth’s killer. A supernova is the explosion of a dying star. It happens once every 100 years or so in our galaxy. Most of the time, they’re generally far away. But there have been some close ones in record history. While none are close enough to blow our planet up ala Hollywood-style, a close enough supernova can destroy our ozone layer and send deadly radiation pouring down onto our planet. One such star is Betelgeuse. Only 600 light years away. It’s a red giant at the end of it’s life, and it has been unusually active lately.
Stephen Hawking recently said “If aliens visit us, the outcome would be much as when Columbus landed in America, which didn’t turn out well for the Native Americans,” he said. “We only have to look at ourselves to see how intelligent life might develop into something we wouldn’t want to meet.”
According to Dr. Hawking, he believes aliens would likely be hostile, looking to either colonize earth or mine its resources. That wouldn’t be the only problem. Just as in giving aliens viruses could harm them, they could also do the same to us. And they likely did their homework.
This one will certainly happen, but we have a couple billion years to go. Death by sun is pretty straight forward. As the sun ages, it will get bigger. Once it gets to a certain point, Earths oceans will boil away and our planet will be burn to a crisp. Better put on your sunblock SPF 2 million.
This one will also happen for certain. Andromeda, a neighboring galaxy, is on a collision course with the Milky way and expected to merge with it in 3-5 billion years time. There are a few outcomes of this collision regarding Earth. The first is that if we’re on one side when it happens, we will likely get caught in the torrent — stuck in a merger of the two dense centers. This puts Earth right in the middle of two merging super-massive black holes. If we’re on the opposite side when it happens, it will be relatively peaceful and we’ll have one helluva view in our night sky. There is also the possibility that the gravity could fling us completely out of our galaxy hurtling deep into intergalactic space.
There is a mysterious force operating in the universe called “dark energy.” If that sounds scary, it’s because astrophysicists like to come up with scary names for things that are actually code for “We have no idea what this is.”
This energy is causing the expansion of the universe. It is also causing the expansion to speed up. If it continues to speed up, it will cause galaxies to fly apart due to gravity being weaker than the dark energy. It would be like placing marbles on a merry-go-round then spinning it. Shortly after, solar systems would fly apart, then planets, then molecules and then finally, even atoms and subatomic particles would be annihilated. Luckily this might not, and wouldn’t happen for billions upon billions of years.
Also known as the Heat Death. This is what happens when the universe runs out of energy. The entropy of the universe continuously increases until it reaches a maximum value. The moment that happens, heat in the system will be evenly distributed, allowing no room for usable energy (or heat) to exist. Basically, every star runs out of fuel and even black holes eventually evaporate away. Luckily this won’t happen for trillions upon trillions of years. The number is so staggeringly high, it’s tough for our minds to comprehend it.
