What will our descendants be like in 3bn years?

Hi all

My understanding is that life on earth began, give or take, 3.5 billion years ago. So, in another 3.5 billion years’ time, what will we have turned into (this is bearing in mind biological evolution as well as cultural and scientific progress)?

I see a few possibles…

  1. We won’t have any descendants in 3.5bn years, because we will have all died out. Nuclear holocaust, meteorite, killer virus, climate change, whatever…

  2. We will be omniscient, omnipotent and omnipresent God-like beings. If we take into account the rate of scientific and technological progress of the last 200 or so years, and then apply that exponent to the next 3.5 *billion *years, then our level of technological and scientific advancement will allow us to be immortal beings freed from physical/material needs, who exist in all time periods and across the multiverse and dimensions and you-get-the-idea.

  3. We will certainly have lots of cool stuff: space-ships, teleporters, and all that… But we’ll never reach the epic levels of development as described in #2 because, sooner or later, our rate of scientific and technological development will diminish - perhaps owing to restraints on resources. We’ll still be ‘human’ in that we’ll still eat, sleep, have sex, and all those other things. We’d better have space-ships, though, because the earth isn’t going to be a fun place to live in 3 billion years’ time…

Would our descendants still resemble humans? Or, can we assume that if a single-celled organism can evolve into a human in 3.5bn years, that a human would evolve by the same degree of relative complexity in the same time frame? Would technology and biology have essentially ‘fused’ by such time, granting us some degree of immortality?

I know, it’s a bit futile really as no-one could possibly know for sure, but I thought I’d throw it out there :slight_smile:

I think we’ll look like this.

We do know that the sun will gradually grow hotter, and that in roughly 1 billion years, the surface temp will be above boiling, so we’d better go elsewhere if we want to survive.

I’d imagine that over a time frame even that short, there would be some kind of adaptation to our environments- maybe Eloi and Morlocks, maybe some dystopian thing like Idiocracy, maybe nothing outward that we’d notice, but they’re more resistant to radiation or pesticides or something.

To be blunt, I’ll be long dead and won’t care.

“I think we’ll be… giant superbeings, really”


If we as a species don’t get ourselves and other life forms off this rock then we will all be dead long before this. IIRC, we are talking about half a billion years before the sun grows so hot that life as we know it won’t be supported anymore.
So, the only way there will be any descendants (not only of humans but of any earth species) in that time frame, we’d have to have moved out into the wider galaxy and colonized other planets. Which means that we would probably not resemble ourselves in any meaningful way in 3.5 billion years…there might be as many descendant species of humanity (and any other species we take with us) as there are current species on this planet.

Our ancestors weren’t really homo sapiens 1 million years ago. And there are significant physical differences between us and our ancestors just 50000 years ago (probably less than this, actually).

After 1 billion years, our descendants aren’t likely to be the same species as us. And we should expect a fair amount of divergence physically.

Not 50K years ago. At least 200K years ago before you start seeing significant differences, and even then, “significant” is in the eye of the beholder.

As for 3B years in the future, the most likely scenario is that we won’t have any ancestors.

Number 1 seems like the most likely scenario to me.

If not that then we must have colonized other planets, in which case I would expect that there will be speciation between planets, which will result in a variety of different human decedents none of which will look like we do today.

Tech-wise, I think that there will be limits as far as technical development due to several factors including the fact that as our knowledge gets broader it takes longer to learn enough to get to the cutting edge. Most scientists will spend their time rediscovering something that was known but had been forgotten. Also given the long time periods involved there is no reason to believe that technology will always progress. I suspect there will be many periods of sharp technological regress. Finally, no matter how far we progress we will always be limited by the laws of physics.

Sorry. I fall into science jargon during working hours.

“Significant” in terms of measurable, quantifiable differences in a biological sense. It wouldn’t necessarily be immediately visible - with the usual caveats that modern humans enjoy better nutrition/health care leading to taller, healthier specimens.

For example, our brain sizes and body sizes have been changing continuously in a measurable way. For example, our brains are actually smaller now than they were 20000 - 40000 years ago (cite). Some scientists are even postulating it may be a sign of the Idiocracy paradigm (cite). I don’t buy that last part, but it’s interesting that our brains are about a tennis ball smaller than they were 20000 years ago.

3.5 Billion years is a very, very long time. It is roughly the period of time between modern humans and early algae slime that formed Stromatolites. These are some of the earliest life forms on Earth and are thought to be responsible for the creation of much of the oxygen in our atmosphere.


Referring to ‘our descendants’ 3.5 billion years from now is like a few of these slimy rocks having the same conversation. The time period is just too long to be thinking about technological advances, or exosolar migration, or any other meaningful measure of comparison.

Since Homo Sapiens have only been around for a few hundred thousand years and the entire genus Homo for a few million, any discussion of several billion years is kind of silly.

Assuming no large planetary extinction events and assuming exosolar diaspora via space travel and that our current species continues to thrive and that power and resources are not an issue, I would expect that whatever we become would overrun the galaxy in a few million years.

But we humans are currently going through a couple hundred thousand years of exponential growth that can’t really continue long term. What we will need to get much further is an unlimited energy source that provides all our needs, and let’s face it, we will need cheap, doable, faster than light travel, or we are not going anywhere literally.

Space is really, really, really big. Imagine the biggest thing possible. It’s bigger than that.

Or else we will die right here in the solar system long before the sun dies.

The vast majority of them will be dead.

In the year 2525, if man is still alive, if woman can survive…

And you’re worrying about the year 3,500,002,013? Dial it back a bit!

I had a friend who insisted that, a million (not a billion, jst a million) years from now, the United States of America will be as well-known as, say, the Roman Empire is known to us. I very politely disagreed.

A mere million years from now, our descendants will only be recognizable as our descendants by means of sophisticated DNA testing (perhaps by careful paleontological analysis of fossils.)

Multiply this by a thousand? Absolutely unrecognizable.

(If there is ever actually a technological “singularity,” then we’ll have gone off to become space gods. Otherwise, probably we’ll retreat to the level of the other social mammals. Gorillas in the mist.)

I don’t think point 1 is realistic. The longer we live as a species the harder it will be to extinguish us. We will conquer more environments, have better technology and have more numbers. We will probably have the technology to avert deadly meteorites before the end of this century. We know tons about public health to stop the spread of diseases (unlike hundreds of years ago, but civilization still survived w/o that knowledge). Climate change won’t kill us, it’ll just decrease our standard of living.

Point 2 sounds far and away the most likely, it won’t take 3.5 billion years either. We will probably be a godlike species with the powers you describe within 200-500 years. Beyond that, who knows.

As for point 3, if resources are depleted you either find new sources, find alternatives, learn to recycle, or build devices that require fewer limited resources. All it would do is slow the rate of progress, not stop it.

In 3 billion years, you could populate entire planets, as diverse as Earth is, with the descendents of a couple of skin cells.

There will not be something as simple as a few sets of creatures that we can call descendants; there will be entire landscapes of them… or nothing.

Read Olaf Stapledon’s Last and First Man to get an idea of the scale we are talking about. And that’s with 1930s science, covering less than a billion years. For a visual version, check out Dougal Dixon’s Man after Man, which postulates the descendants of humanity radiating into dozens of species in only five million years.

It’s a meaningless question, like asking what was before the Big Bang. At some point the term “descendant” will be meaningless . . . not because we will die out, but because linear reproduction will be long obsolete, as well as thinking in terms of “individuals.”

I don’t think the OP requires either lineal descent or individuality. If you prefer, think of it as “what will be the legacy of the human race…”

That said, yeah, 3bn years is not just a very long time, it’s really beyond human comprehension. The most far-out (serious) future speculations I’ve ever seen didn’t require time scales like that.

A more interesting and realistic speculation would bring the focus back about three orders of magnitude.

With that in mind–in three million years I expect that humanity will either be utterly extinct and forgotten, or diversified into many ‘races’ on many worlds, at least some of them non-biological. By which I mean something like computers, not Godlike Beings of Pure Energy.

Somebody will most certainly post this zombie thread with the answer.