Astronomy

When will the Sun end all human life on Earth?

When will the Sun end all human life on Earth?


We are searching data for your request:

Forums and discussions:
Manuals and reference books:
Data from registers:
Wait the end of the search in all databases.
Upon completion, a link will appear to access the found materials.

If nothing else wipes out human existence prior to this, at what point will the Sun make Earth uninhabitable for humans?


The Sun is gradually getting larger and brighter. In fact, as called2voyage pointed out, its brightness is increasing by 1% every 100 million years. You can see how the Sun will change in the future from this graph: (Source)

According to this paper, within 1 billion (short scale) years from now, the ever-increasing luminosity will have made Earth nearly uninhabitable. The average temperature will have reached 47°C, compared to its current 15°C. Essentially no water will be left either, except at the poles. This may allow for simple life to survive for a while.

By 3.5 billion years, Earth will no longer resemble its current self. Its oceans, magnetic field and ozone layer and plate tectonics will be no more. Its surface temperature will skyrocket to roughly 1,330°C, hot enough to melt surface rock. No longer will our planet resemble a pale blue dot, and it will be more like Venus. Our planet is officially dead, along with all life on it. (Source)

~4.5 billion years from now, the Sun will become a red giant and possibly consume Earth. However, according to this paper, it may heat up potentially habitable bodies like Triton, to the point where they would support life. Unfortunately, the Sun won't remain in this stage for long enough - life usually takes billions of years to develop.


At what point will the sun make earth uninhabitable for humans?

It nearly happened on May 23, 1967.
According to this history paper released yesterday, summarized nicely here on Space.com, at the American Geophysical Union (paper publisher), and in many other media outlets, a powerful Earth-directed solar flare on that date jammed radar of the US Air Force's Ballistic Missile Early Warning System. Radar jamming like that, especially across all three sites, was considered an act of war, with the Soviet Union as the obvious culprit. Nuke-laden planes prepared to go destroy the enemy and set off the nuclear war that likely would have rendered Earth uninhabitable for humans.

Fortunately for all of us, the US had invested resources in monitoring the sun several years earlier, and somebody figured out that this was a solar flare with just enough time to stop the nuclear deliveries and keep the Cold War cold.

Popular Mechanics points out:

If that bulletin had been delayed a few minutes, those nuclear aircraft could have launched, and the solar flares would have made it impossible to communicate in the air. If those aircraft had launched, there would have been no way to call them back.


It also nearly happened on September 26, 1983.
With the superpowers again at hair trigger tensions, a rare alignment of sunlight glinting off high altitude clouds and the highly elliptical orbits of Soviet early-warning satellites caused the detection system to report that five intercontinental ballistic missiles, likely carrying nuclear warheads, had been launched by the United States against the Soviet Union. With only a short time to act on such a report, Soviet leaders likely would have launched a large nuclear strike against the US in retaliation for the detected attack. However, the human on duty to receive this detection report was civilian-trained Stanislav Petrov, who was skeptical of the detection and correctly classified this as a false alarm. (Five nuclear missiles seemed small for the kind of attack he expected from the US.) This decision has been credited with preventing a large-scale nuclear war, which otherwise would have been triggered by misinterpreted sunlight.


So a possible answer is, "the next time some tense socio-technical system we've built misinterprets the Sun."

Thanks to user JS for the example from September 1983, and to all those who happened to be in the right place at the right time and helped keep us safe.


According to Wikipedia's timeline of the far future this will happen at least in 800 million years from now:

Carbon dioxide levels fall to the point at which C4 photosynthesis is no longer possible. Free oxygen and ozone disappear from the atmosphere. Multicellular life dies out.

But it might already end 200 million years earlier:

The Sun's increasing luminosity begins to disrupt the carbonate-silicate cycle; higher luminosity increases weathering of surface rocks, which traps carbon dioxide in the ground as carbonate. As water evaporates from the Earth's surface, rocks harden, causing plate tectonics to slow and eventually stop. Without volcanoes to recycle carbon into the Earth's atmosphere, carbon dioxide levels begin to fall. By this time, carbon dioxide levels will fall to the point at which C3 photosynthesis is no longer possible. All plants that utilize C3 photosynthesis (~99 percent of present-day species) will die.


I read a good book that covered the sun expanding scenario. I don't remember the time line but at some point in its lifetime the sun will grow larger and swallow Mercury and the earth will become too hot to sustain life.

I think this is the scenario you're asking about and others have answered, but in the book he points out that over the vast time scales involved, it's not a very big deal for a space faring civilization to move the Earth out to a safe distance then back in when the sun shrinks.

I would have expected some kind of Star Trek level technology, but he describes how to use a simple Gravity tractor (not to be confused with a Tractor Beam) to adjust comets flight paths to speed up the earth (the reverse of the gravity slingshot used to speed up our current space probes) moving it further away from the sun.

So to answer your original question assuming the human life on earth is still advanced and spacefaring, human life on earth could last until the sun burns out and maybe a bit beyond that.


I would be very surprised if the sun ever ends all life on Earth.

1) If we care about the Earth we will move it. If we are still around by then it certainly will be within our technology.

2) I would say the most likely outcome (assuming we survive) is that the Earth gets taken apart for building materials. It's an awful lot of mass simply being used as a gravity source--incredibly inefficient.


How long will life survive on planet Earth?

Life on Earth will surely be wiped out eventually. But how long does it have, and what will it take to sterilise the entire planet?

All things must pass. That includes life on Earth, which will surely be wiped out eventually. But how long does it have?

The fossil record tells us that life on Earth has lasted at least 3.5 billion years. In that time it has survived being frozen, clobbered by rocks from space, mass poisoning, and even lethal radiation. Clearly, it's hard to completely sterilise the planet.

But there's no shortage of potential apocalypses. Which of them will finally render the Earth barren?

Volcanic apocalypse

Timeframe: 0-100 million years? Maybe?

Probably the nearest life has come to ultimate destruction was 250 million years ago, during the end-Permian mass extinction. The event obliterated perhaps 85% of all species living on land - and 95% of all ocean-dwelling species.

Lava smothered an area eight times the size of the UK

No one is quite sure what happened, but it seems to be no coincidence that the extinction coincided with volcanic activity on a truly apocalyptic scale. Today we worry about the destructive power of supervolcanoes like Yellowstone. But the damage they might bring is nothing compared to what happened 250 million years ago.

Back then, Siberia experienced such a large and sustained period of activity that lava smothered an area eight times the size of the UK. Volcanic activity on that scale is rare, but not unheard of.

No one knows when the next such episode will happen, says Henrik Svensen at the University of Oslo in Norway. Similar-sized eruptions happened 200, 180 and 65 million years ago, so they're not terribly regular. But one will surely happen eventually, and when it does the key question will be where it goes off.

Svensen's research suggests that a mega-eruption's ability to wipe out species will depend on exactly where it punches through Earth's crust. That's because the volcanic activity 250 million years ago might not have been directly responsible for the massive extinction. The killer ingredient might have been salt.

It's unlikely that life itself would disappear

Siberia is rich in salt deposits. When they were baked by the volcanic activity, Svensen thinks they released vast quantities of ozone-destroying chemicals into the atmosphere. Species all over the world then had to cope with harmful radiation from space that atmospheric ozone normally soaks up. The stress might well have killed most of them.

The bad news is that there are plenty of massive salt deposits on Earth today. "East Siberia is still among the largest reservoirs," says Svensen. "Offshore Brazil is also big."

If a mega-eruption formed in one of these areas, many species would die. But it's unlikely that life itself would disappear. After all, while plants and animals fared poorly during the end-Permian extinction, single-celled organisms like bacteria sailed through virtually unharmed.

Asteroid threat

Timeframe: within 450 million years, maybe?

It's common knowledge these days that asteroids and dinosaurs don't get along. If a massive asteroid could contribute to the extinction of all of the world's large dinosaurs, could one also wipe out all life on Earth?

Again, that might depend on exactly where the rock lands. We know that the Earth has been hit by some very large asteroids that have barely registered as life destroyers.

Impacts on the scale of the dinosaur killer are rare

The Manicouagan crater in Canada - one of the largest impact craters on the planet - was created in a destructive impact about 215 million years ago. But the fossil record shows it didn't trigger a dinosaur-scale extinction. That might be because the crater formed in relatively inert crystalline rock. Craters that form in volatile-rich sedimentary rocks, in contrast, might send clouds of climate-changing gases into the atmosphere, triggering global mass extinctions.

The good news is that impacts on the scale of the dinosaur killer are rare. Such big rocks may only strike Earth once every 500 million years.

But even if one does come along, mass extinction is unlikely to become mass sterilisation. That would probably only be possible if Earth was hit by something even bigger than an asteroid: a rogue planet.

There might be a precedent for that. Some scientists think Earth was clobbered by a rogue planet soon after it formed, and that the resulting cloud of debris formed the Moon. "We can call this the Melancholia hypothesis, after Lars Von Trier's movie," says Svensen. Still, this possibility seems pretty remote.

When the core freezes over

Timeframe: 3 to 4 billion years

While we're on the subject of movies, consider 2003's The Core. The story is that Earth's core has mysteriously stopped rotating, so the US government backs a plan to drill to the centre of the Earth and restart it &ndash because without an active core, Earth loses its magnetic field and all life is threatened.

Mars once had, and then lost, a magnetic field

The Core is mostly nonsense and has been rightly derided by scientists. But not all of the science it features is junk. Some researchers really do think that Earth's magnetic field deflects ionising particles from the sun, which would otherwise wear away Earth's atmosphere. If they are right, then without a magnetic field our planet will lose its atmosphere too, and all life will die.

Something like this may have happened on Mars, which may once have been more hospitable to life than it is now.

In 1997, Joseph Kirschvink at the California Institute of Technology in Pasadena and his colleagues found good evidence that Mars once had, and then lost, a magnetic field. "The Martian magnetosphere collapsed sometime after 3.7 billion years ago, which is about the time that the planet went into a permanent snowball state," says Kirschvink.

You may have heard that Earth's magnetic field is weakening. But don't worry: that's because the magnetic field is in the process of flipping direction, not dying. These flips have happened periodically for millions of years.

Could Earth's magnetic field eventually disappear?

"If the field reverses, this doesn't mean that it dies out completely," says Richard Holme at the University of Liverpool in the UK. The flip might well do odd things to the magnetic field but "wouldn't greatly disrupt life", he says.

Could Earth's magnetic field eventually disappear? Not any time soon, says Richard Harrison at the University of Cambridge in the UK.

For that to happen the core would have to completely solidify. Currently only the inner core is solid, while the outer core is liquid. "[The inner core] grows about a millimetre a year," says Harrison, and the molten outer core is 2,300 km thick.

Gamma-ray burst

Timeframe: there's a nearby binary star called WR 104 that might produce one within 500,000 years, but even if it does it might well miss us

Are we alone in the universe? And if not, why haven't we made contact with alien civilisations yet? Another life destroyer could be to blame: intense waves of radiation called gamma-ray bursts (GRBs).

Many regions of space may have been rendered inhospitable to life

GRBs are formed by intense explosions in space, for instance when a giant star explodes or two stars collide. They can last a fraction of a second, or several minutes. In theory a long GRB could obliterate Earth's ozone layer, leaving the life on the surface exposed to deadly ultraviolet radiation from the Sun.

Many regions of space may have been rendered inhospitable to life by too-frequent GRBs, according to a study published in 2014 by Raul Jimenez at the University of Barcelona in Spain and Tsvi Piran at the Hebrew University of Jerusalem in Israel. But our neighbourhood may be OK. GRBs happen more often near the centre of the galaxy and in regions where stars are densely packed, and Earth is far away from both.

"Life is present due to the fact that Earth is relatively safe from a true damaging long GRB, those which will cause total extinction," says Jimenez. "If Earth was closer by a factor of two to the centre of the galaxy, life would be gone."

That said, Earth may well have experienced the occasional GRB, and there may even be traces of it in the fossil record. About 440 million years ago, many species were wiped out in the Ordovician-Silurian extinction, which some scientists have suggested was triggered by a GRB.

Humans would be wiped out, but other forms of life would go on

But even if that's true, it didn't even get close to killing everything. There has been warning after warning that deadly GRBs could one day wipe out life on Earth, but it's unlikely that any of the potential nearby sources pose a credible threat.

In even more good news, the rate that GRBs occur is decreasing. James Annis at Fermilab in Batavia, Illinois did some number-crunching for this story, and estimates that the average galaxy will now experience just 5 to 50 GRBs every billion years. Since the Milky Way is big, the chances of any coming near Earth are slim.

Even if a rogue GRB did hit Earth, Annis thinks it would be very unlikely to wipe out all life, because sea water is an excellent radiation shield. "I find it really hard to believe that GRBs could kill off sea vent biomes," he says. "I actually find it hard to believe GRBs would kill most ocean fish. I'm more of the opinion GRBs could kill off ground-based life and maybe the larger surface sea life, sort of resetting the evolution clock back before the colonisation of land."

Of course, humans would be wiped out, but other forms of life would go on.

Wandering stars

Timeframe: possibly within the next million years

For billions of years, the planets of our solar system have been performers in a stately dance around the sun. But what would happen if another star came barrelling through? The idea might sound implausible, but in February 2015 researchers led by Eric Mamajek at the University of Rochester in New York announced that it has happened &ndash and surprisingly recently.

Astronomers have identified other stars on a collision course with the solar system

Just 70,000 years ago, around the time our species left Africa, a red dwarf called Scholz's star cruised through the outer reaches of the solar system. It passed through a region called the Oort cloud, a sparse cluster of small, icy lumps that lies far beyond the planets.

Scholz's star was not the first rogue star to pass through the solar system, and it won't be the last. Astronomers have identified other stars on a collision course with the solar system in the next few million years.

Also in February 2015, Coryn Bailer-Jones at the Max Planck Institute for Astronomy in Heidelberg, Germany highlighted two stars that might prove problematic. Hip 85605 is due in our neighbourhood in 240,000 to 470,000 years, while GL 710 will arrive in about 1.3 million years. GL 710 is "a bit bigger than Scholz's star", says Mamajek, but will probably pass further away. Even so, could it, or Hip 85605, threaten life on Earth?

In a word, no. "Just because a star perturbs the Oort cloud, this does not mean the Earth is doomed," says Bailer-Jones.

Things could get hairy if one of those rogue stars went supernova

Either star could push some of the small objects in the Oort cloud onto a collision course with Earth. But as we've already seen, even if some of them did eventually hit our planet, they probably wouldn't destroy all life.

In theory, things could get hairy if a larger rogue star went supernova as it passed through the Oort cloud, sending gamma rays into the inner solar system. "The nearer the supernova, the most intense [the ionising radiation] is. Ten times nearer, 100 times more intense," says Bailer-Jones. "It could be severe enough to cause real harm." But the chances of that "perfect storm" occurring are slim, he says.

A rogue star would also be more dangerous if it passed through the inner parts of the solar system, where the planets are found. But this is again unlikely. "No star we know of has anything but an extremely small probability of entering the inner solar system," says Bailer-Jones. It's too small a target: the distance from the Earth to the Sun is around 50,000 times smaller than the distance to the edge of the Oort cloud.

There are almost certainly organisms that could survive nearly any cataclysm

Researchers can hypothesise almost no end of threats to life on Earth. February 2015 was evidently apocalypse month: another study suggested that we should even worry about the mysterious "dark matter" in our galaxy. We really shouldn't, says Mamajek, given how little we actually know about dark matter. "We don't know what the dark matter particles are, and we don't know how and if they would annihilate to generate energy," he says.

In fact, the take-home message from all of this research is that there isn't a plausible catastrophic agent from outside the solar system that could wipe out life on Earth within the next few billion years. "There are almost certainly organisms that could survive nearly any cataclysm," says Mamajek.

There is nothing to fear but life itself

Timeframe: 500 million years

But there is one agent of destruction that certainly is powerful enough to wipe out swathes of species. Life's biggest threat could come from within, according to Peter Ward at the University of Washington in Seattle.

The microbes living on Earth could not cope, and a massive extinction followed

He calls the idea the Medea hypothesis. The name is a nod to the famous Gaia hypothesis, named for the Greek goddess of the Earth, which suggests that life helps keep Earth habitable. Medea, in stark contrast, is a Greek mythological figure famous for killing her own children. Ward argues that many of the mass extinctions in Earth's history were caused by life.

For instance, about 2.3 billion years ago lots of oxygen was released into the atmosphere by new forms of photosynthetic life. There had never before been free oxygen, so the microbes living on Earth could not cope with it, and a massive extinction followed.

Then there were the first land plants, about 450 million years ago. Plant roots broke up bedrock into soil, speeding up the chemical reaction between minerals in those rocks and carbon dioxide in the atmosphere. This stripped carbon dioxide from the atmosphere and weakened the greenhouse effect, triggering a lethal ice age.

Fast-forward into Earth's distant future, and these kinds of effects could sterilise the planet, says Ward. The sun is getting hotter as it ages, and as a consequence the Earth will warm up. That means the chemical reaction between rocks and atmospheric carbon dioxide will speed up &ndash a process that's accelerated even more by the action of plant roots.

Alien forensic scientists might well conclude that life on Earth had a hand in its own demise

Eventually, so much carbon dioxide will have been removed from the air that plants can no longer perform photosynthesis. All plants will die, and animal life won't be far behind. This could happen surprisingly soon, says Ward, perhaps in just 500 million years.

There would still be microbes, but they'd be vulnerable. "When you're down to a few microbes and you don't have a strong system, that's when physical perturbations could bring about mass sterilisation," says Ward.

Just as in Agatha Christie's Murder on the Orient Express &ndash spoilers for a novel published in 1934 &ndash it would probably take several killers, acting at roughly the same time, to destroy all life on Earth, says Ward. "They could be large impacts, or nearby supernovae, or even something like freezing of the core. No one single event is going to do it." But if a big rock or GRB was to hit Earth after life had culled itself, mass sterilisation might just follow.

Alien forensic scientists might well conclude that life on Earth had a hand in its own demise.

Expanding Sun

Timeframe: between 1 and 7.5 billion years

If none of that gets us, the Sun will. Our home star bathes us in light, and supplies the energy for almost all the life on Earth. But it won't be friendly forever.

As we saw earlier, the Sun is gradually getting hotter. Eventually it will be hot enough to evaporate all Earth's oceans, and cause a runaway greenhouse effect that sends temperatures soaring upwards. This process might begin in about a billion years, and would wipe out all but the most resistant microorganisms.

But that's not all. Beginning around 5 billion years from now, the Sun will expand, becoming a swollen star called a red giant. By 7.5 billion years in the future, its surface will be past where Earth's orbit is now. So the expanding Sun will engulf, and destroy, the Earth.

It's been suggested that Earth might escape. The Sun will lose mass as it grows, so Earth will spiral further out. But according to calculations performed in 2008, this won't be enough to save our planet.

If that's true, the only hope lies with us. If any humans are still around, they might have the technology to move the Earth to safety. Otherwise, life on Earth has a maximum life expectancy of 7.5 billion years.


Asteroid Impact Apocalypse

When a city-sized asteroid struck the Gulf of Mexico 66 million years ago , it was game over for the dinosaurs, as well as most other species on Earth at the time. And while our ancestors hadn’t yet evolved, the impact was perhaps the single most important event in human history. Without that asteroid strike, dinosaurs might have continued to rule the Earth, leaving us mammals still cowering in the shadows.

Humans, however, won’t always be on the winning side of such random events. A future asteroid could just as easily take out every person on Earth. Fortunately, that’s unlikely to happen anytime soon. Based on the geological record of cosmic impacts, Earth gets hit by a large asteroid roughly every 100 million years, according to NASA . However, smaller asteroid impacts do happen all the time. There’s even evidence that some people may have been killed by small meteorite impacts within the past few thousand years.

But what are the chances that our planet will ever be struck by an asteroid massive enough to wipe out all life on Earth? Simulations published in Nature back in 2017 suggest it would take a truly gigantic space rock to accomplish such a feat. Killing all life on Earth would require an impact that literally boils away the oceans. And only asteroids like Pallas and Vesta — the solar system’s largest — are big enough to do that. There is evidence that infant Earth was struck by a large planetoid called Theia . But these days, collisions of such large objects are extremely unlikely.


5 Killer Events From Space That Could Wipe Out Human Life On Earth

The Earth as viewed from a composite of NASA satellite images from space in the early 2000s. While . [+] it may seem like a tall order to end all human life on the planet from an external threat, the Universe is more than up to the challenge.

NASA / Blue Marble Project

Wiping out all life on Earth is hard, but causing mass extinctions is easy.

The 1991 eruption of Mt. Pinatubo was the largest volcanic eruption to occur in our lifetimes. One . [+] that was perhaps 10,000 times the magnitude of this could threaten human life on Earth, and perhaps volcanism was the cause of at least one of our previous major mass extinctions.

Five major extinction events have occurred since the Cambrian explosion, each eradicating over 60% of terrestrial species.

A measure of biodiversity, and changes in the number of genera that exist at any given time, to . [+] identify the most major extinction events in the past 500 million years. They are not periodic, and only the most recent one (from 65 million years ago) has a known cause.

Wikimedia Commons user Albert Mestre, with data from Rohde, R.A., and Muller, R.A.

At least five extraterrestrial scenarios are capable of wiping humanity out.

A large, rapidly moving mass that strikes the Earth would be certainly capable of causing a mass . [+] extinction event. However, such events appear to be relatively rare. Even though asteroid and comet strikes are frequent, one that causes a mass extinction may be rare enough that no such strikes will occur for billions of years.

Don Davis (work commissioned by NASA)

1.) Asteroid/comet strike: a giant impact triggered the last great mass extinction 65 million years ago.

The comet that gives rise to the Perseid meteor shower, Comet Swift-Tuttle, was photographed during . [+] its last pass into the inner Solar System in 1992. The influence of the gravity of the other planets has the potential to dramatically change its orbit, however, making it a potential threat to Earth in the year 4479. It has been called the single most dangerous object known to humanity by NASA.

Comet Swift-Tuttle, which could strike Earth in 4479, carries 28 times the destructive energy of that event.

This illustration of the most distant gamma-ray burst ever detected, GRB 090423, is thought to be . [+] typical of most fast gamma-ray bursts. When one or two objects violently form a black hole, such as from a neutron star merger, a brief burst of gamma rays followed by an infrared afterglow (when we're lucky) allows us to learn more about these events. The gamma rays from this event lasted just 10 seconds, but Nial Tanvir and his team found an infrared afterglow using the UKIRT telescope just 20 minutes after the burst.

2.) Gamma-ray burst: the brightest electromagnetic events of all are a once-per-million-years risk.

What we perceive as a gamma ray burst is now known to have at least one identified cause: in merging . [+] neutron stars. If one of the jets from these mergers is pointed at Earth, and is close enough (within about 6,000 light-years), it could destroy the ozone layer, which would lead to humanity's demise.

If one occurred within 6,000 light-years of Earth, it would destroy our ozone layer, causing a mass extinction.

70,000 years ago, a brown dwarf pair known as Scholz's Star, right on the precipice of igniting . [+] hydrogen fusion in its core, passed through the Solar System's Oort cloud. Stars, failed stars, and stellar remnants pass through our Solar System multiple times every million years.

3.) A random encounter: the galaxy is full of stars, planets, stellar remnants, and black holes.

Over our Solar System’s 4.5 billion year history, the odds that a star would come as close to any of . [+] the planets as our Sun is to Pluto is approximately 1-in-10,000 the odds that a star would come as close to a planet as the Sun is to Earth (which would severely disrupt our orbit and cause Earth's gravitational ejection) is less than 1-in-1,000,000,000. But if it happened, Earth would freeze over in short order, and human life would go extinct.

If one passes through our inner Solar System, it could gravitationally eject the Earth, destroying us all.

An optical composite/mosaic of the Crab Nebula as taken with the Hubble Space Telescope. The . [+] different colors correspond to different elements, and reveal the presence of hydrogen, oxygen, silicon and more, all segregated by mass. If the Earth were located within this nebula, which extends about 10 light-years across at present, it could cause an extinction-level event for humanity.

NASA, ESA, J. Hester and A. Loll (Arizona State University)

4.) A supernova: these have affected Earth many times, but we have endured without significant harm.

The supernova remnant Cassiopeia A contains signatures of a wide variety of elements of the periodic . [+] table, and would have emitted tremendous amounts of radiation when it first exploded. Type II supernovae are the most common class of supernova, but one would have to occur just a few light-years from us to eliminate our ozone layer, which should be rare enough that the estimated frequency is less than once per few billion years.

A Type II supernova must occur within <25 light-years of Earth to endanger us, an extremely uncommon occurrence.

The Sun has increased in size, brightness, and temperature according to the curves above, and those . [+] three quantities will continue to evolve as shown by their respective lines into the future. By the time another

2 billion years pass, its luminosity will be large enough to boil Earth's oceans, effectively ending life on our planet.

Wikimedia Commons user RJHall, based on Ribas, Ignasi (2010)

5.) Our own Sun: it will eventually incinerate us.

Today on Earth, ocean water only boils, typically, when lava or some other superheated material . [+] enters it. But in the far future, the Sun's energy will be enough to do it, and on a global scale.

Jennifer Williams / flickr

After 2 billion years, the Sun's increasing energy output will boil the oceans, unambiguously terminating all life on Earth.

If all else fails, we can be certain that the evolution of the Sun will be the death of all life on . [+] Earth. Long before we reach the red giant stage, stellar evolution will cause the Sun's luminosity to increase significantly enough to boil Earth's oceans, which will surely eradicate humanity, if not all life on Earth.


When will the Sun end all human life on Earth? - Astronomy

Hi I am a novelist from Norway and I have some questions concerning the death of the sun.
My questions:
If the Sun became a red giant will the Earth still be able to support life here?

Jagadheep: No, the Earth will not be able to support life if the Sun becomes a giant star. Giant stars have large radii as their name implies. When the Sun becomes a giant star, it may become so large as to engulf Earth, in which case the planet will be destroyed. Even if this does not happen, the sun will expand so far out that the temperatures on Earth will become extremely high so that all oceans will evaporate away, and there will be no water left on Earth. So, no life which depends on water will be able to survive.

When the sun starts expanding in about 5 billion years, what will be the first signs of this process?

Karen: The Sun is a relatively low mass star and as such its death will be relatively mundane (at least by Astronomical standards). The Sun's luminosity and radius have been increasing since it started life and will continue to gradually increase in this manner for another 4.5 billion years or so. When the hydrogen in the core is all used up energy generation will stop there, however it will continue in a thin shell around the core. It is this which makes the Sun expand since it heats up the outer layers more. Funnilly enough this makes the very outer layer cooler so that sun will actually redden as well as becoming brighter and expanding. I suspect that this reddening might be the first signs the the Sun has left the Main Sequence.

How long will it take from the process starts til the earth is engulfed, or at least uninhabitable?

Timescales are difficult in evolutionary models of stars. It's not clear quite what'll happen to the Earth either. It could be engulfed by the Sun, or it might get pushed out into a larger orbit and freeze as the Sun expands. The Sun will be a Red Giant for a few million years. By then I think it's safe to say that the Earth will be uninhabitable.

Will the earth catch fire while humans still live here or will the planet simply dry out?

I think that the temperature would kill life before anything caught on fire. It would only need to be 100F or so all the time for humans to be wiped out (we don't survive long in the desert, right).

Is it probable that life on earth will survive that long, or will asteroids wipe us out before then?

Probability wise, it's likely that the Human Race will have been killed off by the time the Sun leaves the Main Sequence. I don't think that any species in history has dominated the Earth for that long. Of course we could be the first.

This page was last updated on June 27, 2015.

About the Author

Jagadheep D. Pandian

Jagadheep built a new receiver for the Arecibo radio telescope that works between 6 and 8 GHz. He studies 6.7 GHz methanol masers in our Galaxy. These masers occur at sites where massive stars are being born. He got his Ph.D from Cornell in January 2007 and was a postdoctoral fellow at the Max Planck Insitute for Radio Astronomy in Germany. After that, he worked at the Institute for Astronomy at the University of Hawaii as the Submillimeter Postdoctoral Fellow. Jagadheep is currently at the Indian Institute of Space Scence and Technology.


How to ensure the (semi)-longevity of our species

Loeb, who is the chair of Harvard University's astronomy department, wrote that humanity needs to "contemplate space travel out of the solar system."

In order to do so, he added, we need to build "an artificial world" capable of bouncing between stars and their neighboring, potentially habitable planets. This industrial spacecraft and human habitat would "represent a very major upgrade to the International Space Station (ISS)," he said.

Once our means of traveling to other planets and moons in the universe is secured, humanity needs to focus on duplicating itself, and other existing species, before we all get annihilated.

"The longer-term solution to our existential threats is not to keep all of our eggs in one basket," Loeb wrote. To him, that means making genetically identical copies of ourselves, plants, and animals, and spreading those copies to other stars.

Obviously, the astronomer pointed out, that future solution won't do much for preserving people alive on Earth today. But to Loeb, its more important to ensure the longevity of our species as a whole rather than protecting "our own skin."


Impacts in Our Future?

The impacts by asteroids and comets that have had such a major influence on life are not necessarily a thing of the past. In the full scope of planetary history, 65 million years ago was just yesterday. Earth actually orbits the Sun within a sort of cosmic shooting gallery, and although major impacts are rare, they are by no means over. Humanity could suffer the same fate as the dinosaurs, or lose a city to the much more frequent impacts like the one over Tunguska, unless we figure out a way to predict the next big impact and to protect our planet. The fact that our solar system is home to some very large planets in outer orbits may be beneficial to us the gravitational fields of those planets can be very effective at pulling in cosmic debris and shielding us from larger, more frequent impacts.

Beginning in the 1990s, a few astronomers began to analyze the cosmic impact hazard and to persuade the government to support a search for potentially hazardous asteroids. Several small but sophisticated wide-field telescopes are now used for this search, which is called the NASA Spaceguard Survey. Already we know that there are currently no asteroids on a collision course with Earth that are as big (10–15 kilometers) as the one that killed the dinosaurs. The Spaceguard Survey now concentrates on finding smaller potential impactors. By 2015, the search had netted more than 15,000 near-Earth-asteroids, including most of those larger than 1 kilometer. None of those discovered so far poses any danger to us. Of course, we cannot make a similar statement about the asteroids that have not yet been discovered, but these will be found and evaluated one by one for their potential hazard. These asteroid surveys are one of the few really life-and-death projects carried out by astronomers, with a potential to help to save our planet from future major impacts.

The Torino Impact Hazard Scale is a method for categorizing the impact hazard associated with near-Earth objects such as asteroids and comets. It is a communication tool for astronomers and the public to assess the seriousness of collision predictions by combining probability statistics and known kinetic damage potentials into a single threat value.

Purdue University’s “Impact: Earth” calculator lets you input the characteristics of an approaching asteroid to determine the effect of its impact on our planet.

Key Concepts and Summary

Earth, like the Moon and other planets, has been influenced by the impacts of cosmic debris, including such recent examples as Meteor Crater and the Tunguska explosion. Larger past impacts are implicated in some mass extinctions, including the large impact 65 million years ago at the end of the Cretaceous period that wiped out the dinosaurs and many other species. Today, astronomers are working to predict the next impact in advance, while other scientists are coming to grips with the effect of impacts on the evolution and diversity of life on Earth.


When will the Sun end all human life on Earth? - Astronomy

Hi I am a novelist from Norway and I have some questions concerning the death of the sun.
My questions:
If the Sun became a red giant will the Earth still be able to support life here?

Jagadheep: No, the Earth will not be able to support life if the Sun becomes a giant star. Giant stars have large radii as their name implies. When the Sun becomes a giant star, it may become so large as to engulf Earth, in which case the planet will be destroyed. Even if this does not happen, the sun will expand so far out that the temperatures on Earth will become extremely high so that all oceans will evaporate away, and there will be no water left on Earth. So, no life which depends on water will be able to survive.

When the sun starts expanding in about 5 billion years, what will be the first signs of this process?

Karen: The Sun is a relatively low mass star and as such its death will be relatively mundane (at least by Astronomical standards). The Sun's luminosity and radius have been increasing since it started life and will continue to gradually increase in this manner for another 4.5 billion years or so. When the hydrogen in the core is all used up energy generation will stop there, however it will continue in a thin shell around the core. It is this which makes the Sun expand since it heats up the outer layers more. Funnilly enough this makes the very outer layer cooler so that sun will actually redden as well as becoming brighter and expanding. I suspect that this reddening might be the first signs the the Sun has left the Main Sequence.

How long will it take from the process starts til the earth is engulfed, or at least uninhabitable?

Timescales are difficult in evolutionary models of stars. It's not clear quite what'll happen to the Earth either. It could be engulfed by the Sun, or it might get pushed out into a larger orbit and freeze as the Sun expands. The Sun will be a Red Giant for a few million years. By then I think it's safe to say that the Earth will be uninhabitable.

Will the earth catch fire while humans still live here or will the planet simply dry out?

I think that the temperature would kill life before anything caught on fire. It would only need to be 100F or so all the time for humans to be wiped out (we don't survive long in the desert, right).

Is it probable that life on earth will survive that long, or will asteroids wipe us out before then?

Probability wise, it's likely that the Human Race will have been killed off by the time the Sun leaves the Main Sequence. I don't think that any species in history has dominated the Earth for that long. Of course we could be the first.

This page was last updated on June 27, 2015.

About the Author

Jagadheep D. Pandian

Jagadheep built a new receiver for the Arecibo radio telescope that works between 6 and 8 GHz. He studies 6.7 GHz methanol masers in our Galaxy. These masers occur at sites where massive stars are being born. He got his Ph.D from Cornell in January 2007 and was a postdoctoral fellow at the Max Planck Insitute for Radio Astronomy in Germany. After that, he worked at the Institute for Astronomy at the University of Hawaii as the Submillimeter Postdoctoral Fellow. Jagadheep is currently at the Indian Institute of Space Scence and Technology.


End of the world: Astronomer warns Earth will boil as the Sun grows brighter and bigger

Link copied

Brian Cox reveals how the sun could end life on Earth

When you subscribe we will use the information you provide to send you these newsletters. Sometimes they'll include recommendations for other related newsletters or services we offer. Our Privacy Notice explains more about how we use your data, and your rights. You can unsubscribe at any time.

Astronomers studying the fiery demise of the planet Venus fear a similar fate awaits our home planet. Venus is the second planet from the Sun, named after the Roman goddess of love. The planet in many ways resembles the shape and structure of our Earth. But the alien world is a blistering-hot planet choked out by its own thick and toxic atmosphere of mainly carbon dioxide.

Related articles

According to space agency NASA, surface temperatures on Venus that are exacerbated by the greenhouse effect, are hot enough to melt lead.

The atmospheric pressures on Venus are around 90 times stronger than those on Earth, making the planet an incredibly inhospitable environment.

The description paints a bleak picture of our cosmic neighbour and the trouble is, the Earth could suffer the same conditions in the future. All thanks to the burning star at the heart of our solar system.

Astrophysicist Paul M Sutter from Ohio State University explained how the Sun will contribute to the Earth&rsquos demise.

End of the world: The Sun will one day boil the Earth's oceans and atmosphere (Image: GETTY)

End of the world: The planet Venus suffered a fiery demise at the hands of the Sun (Image: GETTY)

In an article for Space.com, the space expert argued the Sun has not yet reached its full potential and is still growing brighter.

Four billion years ago, Venus resembled the Earth but the Sun was considerably smaller and dimmer.

With time, however, the Sun steadily grew brighter and brighter, causing surface temperatures on Venus to rise.

Gradually, the planet&rsquos oceans began to evaporate, blotting out the skies with enough water vapour to cause a catastrophic greenhouse gas.

Related articles

As the oceans evaporated, the planet&rsquos plate tectonics came to a grinding halt, carbon dioxide locked in the earth began to leak into the atmosphere and &ldquothings spiralled out of control&rdquo.

This is our fate, too

Paul Sutter, Ohio State University

Dr Sutter said: &ldquoThe atmosphere might even have had enough drag to literally slow down the rotation of Venus itself, giving it its present-day sluggish rates.

&ldquoOnce this process was complete, which probably took 100 million years or so, the potential for any life on Venus was snuffed out.

&ldquoAnd here&rsquos the worst part about the story of Earth&rsquos twisted sister. This is our fate, too.&rdquo

Venus once had similar temperatures to a 'Spring day' says Cox

According to NASA, the Sun&rsquos expansion is caused by the rapid burning of helium at the core, which causes surface layers of the star to expand.

As the star expands, the habitability zone around the star shrinks, making it harder for life to exist.

This process of expansion has been going since the Sun formed 4.5 billion years ago.

Thankfully, in the last four billion years the Sun has barely grown by 20 percent &ldquoat most&rdquo.

End of the world: The Sun is still growing as it burns off its helium (Image: GETTY)

End of the world: It will be billions of years before the Earth dies from the Sun (Image: GETTY)

NASA said: &ldquoIt will not grow by much more than another factor of a few for the next six billion years, but at that distant time, it will make a rapid transition to a red giant phase and its outer surface will expand by several hundred times to perhaps the orbit of Venus.

&ldquoAstronomers have searched for short term changes in the radius of the Sun, but have not been able to find much reliable evidence that the sun's diameter is changing, at least over times as short as the solar cycle.&rdquo

This means we do not have to worry about armageddon for another six billion years or so.

By the time it does happen, however, Dr Sutter said &ldquoour solar system will be home to not just one hell but two&rdquo.


Ancient practice of sun worshiping

Primitive people worshipped the Sun and were afraid when it would disappear during an eclipse. Humans since time immemorial have worshipped the sun – In ancient Egyptian mythology, the name of the “Sun” god was “Ra”, the one who “ra”diates. Few Native American tribes, such as the Iroquois and Plains, recognize the sun as a life-giving force.

Many Plains tribes still perform a Sun Dance each year, as a sign of renewal of the bond man has with life, earth, and the growing season.

“Ô, Sunlight! The most precious gold to be found on Earth.” ― Roman Payne

Ancient Greeks used sunlight as a form of therapy, now known as heliotherapy. Surya is glorified in the Vedas of ancient India as an all-seeing god who observes both good and evil actions. He expels not only darkness but also evil dreams and diseases.

In Yoga, Surya Namaskar or Sun Salutation is an ancient technique of expressing gratitude to the Sun that is the source of all forms of life on Earth.
The solar plexus is said to be connected with the Sun, and regular practice of Surya Namaskar enhances your creative and intuitive abilities. Sunlight is helpful in curing depression as it is known to increase serotonin activity in one’s body. Not to forget, it is an important source of Vitamin D.


Contacting aliens could end all life on Earth. Let’s stop trying.

/>The image from video provided by the Department of Defense labelled Gimbal, from 2015, an unexplained object is seen at center as it is tracked as it soars high along the clouds, traveling against the wind. “There's a whole fleet of them,” one naval aviator tells another, though only one indistinct object is shown. “It's rotating." The U.S. government has been taking a hard look at unidentified flying objects, under orders from Congress, and a report summarizing what officials know is expected to come out in June 2021. (Department of Defense via AP)

The image from video provided by the Department of Defense labelled Gimbal, from 2015, an unexplained object is seen at center as it is tracked as it soars high along the clouds, traveling against the wind. “There's a whole fleet of them,” one naval aviator tells another, though only one indistinct object is shown. “It's rotating." The U.S. government has been taking a hard look at unidentified flying objects, under orders from Congress, and a report summarizing what officials know is expected to come out in June 2021. (Department of Defense via AP)

In April 2020, the Defense Department released videos recorded by infrared cameras on U.S. Navy aircraft that documented the planes’ encounters with a variety of “unidentified aerial phenomena.” Pilots reported seeing objects flying across the sky at hypersonic speeds and changing direction almost instantaneously, capabilities far beyond that of any known aircraft.

What were the pilots seeing? Bizarre atmospheric phenomena? Alien spacecraft? Something else? Several branches of the government have been investigating the events, motivated in part by concern that adversaries such as Russia or China might have made some spectacular technological advance, and later this month, the government plans to publish a report revealing what they know. Reportedly, the government will say there’s no proof of extraterrestrial activity, but that the incidents remain unexplained.

Chances are, though, that we should all be grateful that we don’t yet have any evidence of contact with alien civilizations. Attempting to communicate with extraterrestrials, if they do exist, could be extremely dangerous for us. We need to figure out whether it’s wise — or safe — and how to handle such attempts in an organized manner.

Some scientific circles have already been debating questions around whether to try to contact other civilizations. It’s a topic of profound importance for the entire planet. For 60 years, scientists have been searching with radio telescopes, listening in for possible signals coming from other civilizations on planets orbiting distant stars. These efforts have largely been organized by the SETI institute in California — the acronym stands for Search for ExtraTerrestrial Intelligence — and so far, they’ve had no success. Getting impatient, some other scientists are now pushing for a more active program — METI, for Messaging ExtraTerrestrial Intelligence — that wouldn’t just listen, but actually send out powerful messages toward other stars, seeking to make contact.

The search for aliens has reached a stage of technological sophistication and associated risk that it needs strict regulation at national and international levels. Without oversight, even one person — with access to powerful transmitting technology — could take actions affecting the future of the entire planet.

That’s because any aliens we ultimately encounter will likely be far more technologically advanced than we are, for a simple reason: Most stars in our galaxy are much older than the sun. If civilizations arise fairly frequently on some planets, then there ought to be many civilizations in our galaxy millions of years more advanced than our own. Many of these would likely have taken significant steps to begin exploring and possibly colonizing the galaxy.

Hence, it’s a profound mystery — known as the Fermi Paradox, after the Italian physicist Enrico Fermi — why we haven’t yet seen any such aliens. Many resolutions of the paradox have been proposed, among them the suggestion that all civilizations, once reaching sufficient technological capacity, eventually destroy themselves. Or perhaps aliens are so alien and unlike humans that we simply cannot interact with them.

More alarming is the possibility that alien civilizations are remaining out of contact because they know something: that sending out signals is catastrophically risky. Our history on Earth has given us many examples of what can happen when civilizations with unequal technology meet — generally, the technologically more advanced has destroyed or enslaved the other. A cosmic version of this reality might have convinced many alien civilizations to remain silent. Exposing yourself is an invitation to be preyed upon and devoured.

I’ve written about METI in the past, suggesting such activity takes a huge risk for very little gain. But these concerns don’t convince supporters of trying it, who have some counterarguments. Douglas Vakoch of METI International argues that it’s unrealistic to worry about the danger of an alien invasion. We have, after all, been sending radio and television emissions into space for a century, and a civilization far more advanced than our own will probably have already detected these. If they wanted to invade, they already would have.

He also argues that, in assessing risks, it’s important not only to consider the risk coming from taking an action, but also from not taking that action. Our world faces a number of potentially existential threats, including global warming and destabilization of the environment, and it’s possible that far more advanced civilizations may have already faced these issues and found solutions. If we don’t send out signals, Vakosh writes, we risk “missing guidance that could enhance our own civilization’s sustainability.” It’s also conceivable, he suggests, that we’re making a spectacular misjudgment — and some super-advanced alien civilization may attack us precisely because we haven’t reached out.

For obvious reasons, much of the thinking about these issues has to be rather speculative. The best way forward, perhaps, is to broaden the discussion. If all of humanity is exposed to the possible consequences trying to contact alien civilizations, then more people should be involved in making decisions about what is wise and what isn’t. It shouldn’t be left to a handful of radio astronomers.

One vocal critic of the idea of reaching out to aliens proactively — astronomer John Gertz of SETI — has developed proposals to move toward more inclusive public consideration of these activities. What we need, he suggests, are laws and international treaties to govern more explicit contact attempts. Without prior broad agreement from some globally representative body, Gertz says, contacting extraterrestrials should be considered “as the reckless endangerment of all mankind, and be absolutely proscribed with criminal consequences, presumably as exercised at the national level, or administered through the International Court of Justice in The Hague.”

Currently, no such prohibitions exist. Some informal protocols for interacting with alien civilizations have been informally adopted by researchers involved in SETI, but these are far from legally binding governmental regulations. That’s mostly because, up to now, talking about meeting or contacting aliens has seemed widely speculative — if not a little deranged — despite the apparent scientific plausibility of such an event.

It’s not easy to weigh the pros and cons of activities around which so much remains unknown. We don’t know if there are any aliens. They might be friendly. They might not be. Given the potential risks involved with trying to make contact, perhaps it would be safer and wiser to just wait — we can always reach out later, and meanwhile, our abilities to do passive listening are rapidly growing more powerful.

In 2015, SETI launched a new 10-year program called Breakthrough Listen, funded by a $100 million donation from Russian billionaire Yuri Milner. As a result, SETI is now recording more signals than ever before, over a frequency range some tenfold larger, and bringing more computational power to bear on analyzing the recorded signals. It’s impossible to know how close or far from making a discovery we may be, but Gertz estimates that our chances are at least 100 times greater than they used to be.

The search is also benefiting from astronomers’ knowledge of exoplanets — planets in orbit around stars other than the sun. Since the first exoplanet was found in 1992, we’ve identified nearly 5,000 more, and the rate of discovery is accelerating. Each one give SETI researchers new promising targets to scrutinize.

Personally, all of this makes me dead-set against any experimentation with attempting to contact other civilizations. Why take cosmic risks when we may have a far safer pathway to discovering them, if they’re out there? Of course, even listening comes with some potentially fraught governance issues also: If and when someone really identifies an alien signal, we’ll need to decide if we should reply — and if so, how. Surely such an act — putting all of humanity at risk — ought to be the result of some collective decision. But there’s no mechanism to encourage that now. Any individual or nation could take the human response into their own hands.

Both paths — listening for aliens or trying to call them — have reached the stage where they require broader public discussion, with an eye to developing sensible regulation. That’s going to take the efforts of leaders from many nations, presumably coordinated through the United Nations or some similar international body. It should happen now. Or soon. Before it’s too late.

Mark Buchanan is a physicist and science writer based in Europe.