Is there another Earth in the universe?

If we have enough time, could we find another planet in the universe where we could survive as humans? 

We won’t know the final answer to this question unless we actually find it.  Not finding it doesn’t mean it’s not there;  it just means we have to keep looking.  But we can look at the pros and cons of our finally making a successful search.

On the optimistic side of the ledger is the fact that space is so huge that it is almost beyond human imagination to grasp.  And it’s an incredibly dynamic place, so the possibilities are immense.  For that reason, many scientists think the likelihood of there being other planets like our Earth is high.

We are also getting much better at spotting the tell-tale signs of planets orbiting around a star.  The gravity created by a planet pull creates a slight wobble in the path of light emitted by the star which modern-day telescopes are increasingly able to spot.  Especially if the telescope, like the Hubble telescope, is sending back images from deep outer space.  So new planets are being discovered almost everyday.

Unfortunately, almost all the planets in the universe, including all the other planets in our own solar system, are decidedly inhospitable for folk like us.  They are too hot, too cold, too dry, too rocky, bombarded by lethal radiation and other objects, big and small, smashing into them.  Most critically, many are without oxygen, hydrogen, and carbon, the very fabric of all life as we know it.

The scary possibility is that Earth, even in our vast Universe, is unique:

First of all, our solar system was formed five billion years ago when the universe was already more than eight billion years old.  We are located in a fairly old part of the universe where many stars had lived and died, leaving behind that precious cache of oxygen, hydrogen, and carbon. 

Then Earth has a magnetic centre, which most planets do not have.  This isn’t just valuable because it gives us a working compass and holds our magnets onto the refrigerator door.  Most critically, it diverts many of the lethal rays of the sun around the planet.

Earth has several big brothers that protect it from the bombardment of many of biggest loose chunks of material flinging around space.  Jupiter is our biggest protector, taking the blows that would otherwise run into us and disrupt the sustained development of life.

And as we all know, Earth has a supply of oxygen for us to breathe, and an ozone layer that  is an additional protection for life forms that don’t live immersed in the sea.  Earth wasn’t made with the oxygen we breathe.  In fact, it took two billion years for it to be developed by bacteria that expelled oxygen the way we now expel carbon-dioxide when we breathe out.  Nor was the ozone level was not deep enough to protect animal life until close to half a billion years ago when fish followed plant life onto solid ground.

There are those who ask if we might be able to re-engineer a nearby planet to make it hospitable for us.  They look particularly at Mars.  Could we hang a great solar blanket behind Mars to catch the rays of the Sun, thus warming it?  If we could, and if there’s water on Mars, would it be possible to bring in enough photosynthesizing plants to create an atmosphere of oxygen for us to breathe and grow food for us to eat?    One estimate is that this could conceivably be done within the next thousand years. 

The problems would be immense, but as we shall see in the next post, it would be a doddle compared to the problems that would have to be solved if we must actually leave our current galaxy to find an alternative to Earth.


About Terry Sissons

Terry Sissons is the author of The Big Bang to Now: All of Time in Six Chunks, and this blog is a dialogue about the universe and what’s happened in the last 13 billions years.
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4 Responses to Is there another Earth in the universe?

  1. ryan savage says:

    i totally agree with your thoughts. If we were to create some sort of blanket around mars to catch all of the rays i believe that we could make another planet to obtain human life. I also believe that somewhere out there, there has to be some sort of human life besides us on earth. The galaxy never ends and there are many more solar systems and what not far far beyond us knowing.

    • It’s astonishing what we have already discovered about the universe and what we have done during the time humans have existed on this planet, isn’t it? And when you think about it, it will probably be just as mind-boggling what we discover and what we do in the next century – let along the next millennium.
      My hunch, like yours, is that the universe is teeming with life of all kinds. Wonder if any of us will live long enough to be in on discovery. Though I’m not sure alien life would necessarily be friendly. Given our own response to life we don’t understand, other aliens might not be all that happy to see us either. What do you think?

  2. Adewole opeyemi says:

    What u said was true that there may be other Earths in other galaxies,universe etc.According to x-men that i watched,there were other earths but there is one earth that is different called prime earth at centre of the universe which if it is destroyed other earth will be destroyed.7t7p5z76

    • There is a difference between scientific theory and science fiction. They often both deal with the same questions — is there life beyond this Earth? for instance, or are there other Earths? But science fiction does not look for evidence to support its ideas, because it is just a story. Scientific theory, however, does look for objective evidence which either supports or rejects a particular theory.

      Although there is a place for scientific fiction and I often enjoy it, this blog is about ideas based on scientific theory. The ideas of the x-men therefore belong on a different blog than this one.

      Terry Sissons

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