The science of why we can’t live forever
Here's why stars fade out — and so do we.
MICHAEL SHERMER: From a scientist's prospective it's going to be rather different from that of most religious traditions, which holds that we die because this is only a temporary staging area before we go to the big show the next stage in which we go to heaven or hell or wherever some kind of afterlife. For scientists the question has a rather different answer and it has to do with the kinds of causes we look for in science. So you have proximate causes versus ultimate causes. For example, why does sugar taste sweet or why does fruit taste sweet something like that? You would say well because there's molecular receptors on your tongue that are geared toward sending signals to a certain part of the brain that register sweetness and pleasure and so on with fruit. That's approximate answer. And ultimate answer is because foods that taste sweet are more likely to be consumed and those in our natural environment are the kinds of foods that are both rare and nutritious and so the more of them you eat the better and we evolved that tendency.
To answer the question why we die, it's the same kind of thing. Approximate answers include cancer, heart disease, arthrosclerosis. The ultimate answer though is found in two principles of nature, that is the second law of thermodynamics or entropy, which means everything runs down, including our bodies. And the whole universe, the whole universe runs down so ultimately even if you could double your lifespan, triple it, live essentially forever you can't really because the universe will eventually die in a heat death. And then second is the principle of natural selection that drives evolution. And it has to do with a cost benefit analysis of how many limited resources you put into organisms. So obviously natural selection is going to select for infants and toddlers and babies to be well cared for, have super regenerative powers to keep their bodies going in order to get the genes into the next generation, get them up to reproductive age and so on. So we see cells that divide very rapidly in infants and babies. A little cut you could practically watch it heal. It's incredible. Whereas someone my age when I get cut it takes much longer to heal.
And so the question is why wouldn't evolution just make it so that I, now in my early 60s, can't just keep going to 200/300? And the answer is there's no reason for it. Because after I've brought my own offspring into reproductive age and then they've brought their offspring into reproductive age I'm really of no use anymore. I can serve a useful purpose as a parent, of course, bringing my genes up and then useful purpose as a grandparent to help my offspring bring their offspring up to reproductive age, but beyond that really there's no sense in pouring any more resources into great, great, great, great, great grandparents because the genes in the little infant are already going to be well taken care of. So it's sort of a weird way to think about it, but in a way nature operates because of entropy. Nature has to select and choose in kind of a triage where are we going to put the resources. I'm saying it like there's somebody up there allocating resources, the government is doling out checks to organisms. No, there is nothing like that, of course, this is just how natural selection operates. So in short, we die so that our future generations may live because there are limited resources.
- According to scientists the reason we die is because the second law of thermodynamics and natural selection.
- The whole universe runs down, so, ultimately, even if you could lengthen your lifespan indefinitely, the universe itself will eventually die in a heat death.
- We die, one predominant view goes, so that our progeny may live — because there are limited resources.
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- 5 stages of psychogenic death or 'give-up-itis' - Big Think ›
- After death, you're aware that you've died, say scientists - Big Think ›
But most city dwellers weren't seeing the science — they were seeing something out of Blade Runner.
On Sept. 9, many West Coast residents looked out their windows and witnessed a post-apocalyptic landscape: silhouetted cars, buildings and people bathed in an overpowering orange light that looked like a jacked-up sunset.
A study finds 1.8 billion trees and shrubs in the Sahara desert.
- AI analysis of satellite images sees trees and shrubs where human eyes can't.
- At the western edge of the Sahara is more significant vegetation than previously suspected.
- Machine learning trained to recognize trees completed the detailed study in hours.
Why this matters<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDU2MDQ1OC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzOTkyODg5NX0.O3S2DRTyAxh-JZqxGKj9KkC6ndZAloEh4hKhpcyeFDQ/img.jpg?width=980" id="3770d" class="rm-shortcode" data-rm-shortcode-id="3c27b79d4c0600fb6ebb82e650cabec0" data-rm-shortcode-name="rebelmouse-image" />
Area in which trees were located
Credit: University of Copenhagen<p>As important as trees are in fighting climate change, scientists need to know what trees there are, and where, and the study's finding represents a significant addition to the global tree inventory.</p><p>The vegetation Brandt and his colleagues have identified is in the Western Sahara, a region of about 1.3 million square kilometers that includes the desert, <a href="https://en.wikipedia.org/wiki/Sahel" target="_blank">the Sahel</a>, and the <a href="https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/subhumid-zones" target="_blank" rel="noopener noreferrer">sub-humid zones</a> of West Africa.</p><p>These trees and shrubs have been left out of previous tabulations of carbon-processing worldwide forests. Says Brandt, "Trees outside of forested areas are usually not included in climate models, and we know very little about their carbon stocks. They are basically a white spot on maps and an unknown component in the global carbon cycle."</p><p>In addition to being valuable climate-change information, the research can help facilitate strategic development of the region in which the vegetation grows due to a greater understanding of local ecosystems.</p>
Trained for trees<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDU2MDQ3MC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzNTk5NTI3NH0.fR-n1I2DHBIRPLvXv4g0PVM8ciZwSLWorBUUw2wc-Vk/img.jpg?width=980" id="e02c0" class="rm-shortcode" data-rm-shortcode-id="79955b13661dca8b6e19007935129af1" data-rm-shortcode-name="rebelmouse-image" />
Credit: Martin Brandt/University of Copenhagen<p>There's been an assumption that there's hardly enough vegetation outside of forested areas to be worth counting in areas such as this one. As a result the study represents the first time a significant number of trees — likely in the hundreds of millions when shrubs are subtracted from the overall figure — have been catalogued in the drylands region.</p><p>Members of the university's Department of Computer Science trained a machine-learning module to recognize trees by feeding it thousands of pictures of them. This training left the AI be capable of spotting trees in the tiny details of satellite images supplied by NASA. The task took the AI just hours — it would take a human years to perform an equivalent analysis.</p><p>"This technology has enormous potential when it comes to documenting changes on a global scale and ultimately, in contributing towards global climate goals," says co-author Christian Igel. "It is a motivation for us to develop this type of beneficial artificial intelligence."</p><p>"Indeed," says Brandt says, "I think it marks the beginning of a new scientific era."</p>
Looking ahead and beyond<p>The researchers hope to further refine their AI to provide a more detailed accounting of the trees it identifies in satellite photos.</p><p>The study's senior author, Rasmus Fensholt, says, "we are also interested in using satellites to determine tree species, as tree types are significant in relation to their value to local populations who use wood resources as part of their livelihoods. Trees and their fruit are consumed by both livestock and humans, and when preserved in the fields, trees have a positive effect on crop yields because they improve the balance of water and nutrients."</p><p>Ahead is an expansion of the team's tree hunt to a larger area of Africa, with the long-term goal being the creation of a more comprehensive and accurate global database of trees that grow beyond the boundaries of forests.</p>
Famous physicists like Richard Feynman think 137 holds the answers to the Universe.
- The fine structure constant has mystified scientists since the 1800s.
- The number 1/137 might hold the clues to the Grand Unified Theory.
- Relativity, electromagnetism and quantum mechanics are unified by the number.
Younger Americans support expanding the Supreme Court and serious political reforms, says new poll.
- Americans under 40 largely favor major political reforms, finds a new survey.
- The poll revealed that most would want to expand the Supreme Court, impose terms limits, and make it easier to vote.
- Millennials are more liberal and reform-centered than Generation Z.