A record of the sun left on the moon

From NASA Goddard:


  • The Sun’s rotation rate in its first billion years is unknown.
  • Yet, this spin rate affected solar eruptions, influencing the evolution of life.
  • A team of NASA scientists think they’ve figured it out by using the Moon as critical evidence.

Solar flare

NASA’s Solar Dynamics Observatory captured this image of a solar flare on Oct. 2, 2014. The solar flare is the bright flash of light on the right limb of the Sun. A burst of solar material erupting out into space can be seen just below it.Credits: NASA/SDOSolar Flare

The Sun is why we’re here. It’s also why Martians or Venusians are not. 

When the Sun was just a baby four billion years ago, it went through violent outbursts of intense radiation, spewing scorching, high-energy clouds and particles across the solar system. These growing pains helped seed life on early Earth by igniting chemical reactions that kept Earth warm and wet. Yet, these solar tantrums also may have prevented life from emerging on other worlds by stripping them of atmospheres and zapping nourishing chemicals.  

Just how destructive these primordial outbursts were to other worlds would have depended on how quickly the baby Sun rotated on its axis. The faster the Sun turned, the quicker it would have destroyed conditions for habitability.  

This critical piece of the Sun’s history, though, has bedeviled scientists, said Prabal Saxena, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Saxena studies how space weather, the variations in solar activity and other radiation conditions in space, interacts with the surfaces of planets and moons. 

Now, he and other scientists are realizing that the Moon, where NASA will be sending astronauts by 2024, contains clues to the ancient mysteries of the Sun, which are crucial to understanding the development of life.

“We didn’t know what the Sun looked like in its first billion years, and it’s super important because it likely changed how Venus’ atmosphere evolved and how quickly it lost water. It also probably changed how quickly Mars lost its atmosphere, and it changed the atmospheric chemistry of Earth,” Saxena said.    

The Sun-Moon Connection

Saxena stumbled into investigating the early Sun’s rotation mystery while contemplating a seemingly unrelated one: Why, when the Moon and Earth are made of largely the same stuff, is there significantly less sodium and potassium in lunar regolith, or Moon soil, than in Earth soil?   

This question, too, revealed through analyses of Apollo-era Moon samples and lunar meteorites found on Earth, has puzzled scientists for decades — and it has challenged the leading theory of how the Moon formed.    

Apollo 16 sample

A closeup view of Apollo 16 lunar sample no. 68815, a dislodged fragment from a parent boulder roughly four feet high and five feet long.Credits: NASA/JSCApollo 16 Lunar Sample

Our natural satellite took shape, the theory goes, when a Mars-sized object smashed into Earth about 4.5 billion years ago. The force of this crash sent materials spewing into orbit, where they coalesced into the Moon.  

“The Earth and Moon would have formed with similar materials, so the question is, why was the Moon depleted in these elements?” said Rosemary Killen, an planetary scientist at NASA Goddard who researches the effect of space weather on planetary atmospheres and exospheres.   

The two scientists suspected that one big question informed the other — that the history of the Sun is buried in the Moon’s crust.   

Killen’s earlier work laid the foundation for the team’s investigation. In 2012, she helped simulate the effect solar activity has on the amount of sodium and potassium that is either delivered to the Moon’s surface or knocked off by a stream of charged particles from the Sun, known as the solar wind, or by powerful eruptions known as coronal mass ejections. 

Saxena incorporated the mathematical relationship between a star’s rotation rate and its flare activity. This insight was derived by scientists who studied the activity of thousands of stars discovered by NASA’s Kepler space telescope: The faster a star spins, they found, the more violent its ejections. “As you learn about other stars and planets, especially stars like our Sun, you start to get a bigger picture of how the Sun evolved over time,” Saxena said.  

Using sophisticated computer models, Saxena, Killen and colleagues think they may have finally solved both mysteries. Their computer simulations, which they described on May 3 in the The Astrophysical Journal Letters, show that the early Sun rotated slower than 50% of baby stars. According to their estimates, within its first billion years, the Sun took at least 9 to 10 days to complete one rotation.  

They determined this by simulating the evolution of our solar system under a slow, medium, and then a fast-rotating star. And they found that just one version — the slow-rotating star — was able to blast the right amount of charged particles into the Moon’s surface to knock enough sodium and potassium into space over time to leave the amounts we see in Moon rocks today.   

“Space weather was probably one of the major influences for how all the planets of the solar system evolved,” Saxena said, “so any study of habitability of planets needs to consider it.” 

Life Under the Early Sun

The rotation rate of the early Sun is partly responsible for life on Earth. But for Venus and Mars — both rocky planets similar to Earth — it may have precluded it. (Mercury, the closest rocky planet to the Sun, never had a chance.)

Earth’s atmosphere was once very different from the oxygen-dominated one we find today. When Earth formed 4.6 billion years ago, a thin envelope of hydrogen and helium clung to our molten planet. But outbursts from the young Sun stripped away that primordial haze within 200 million years.

As Earth’s crust solidified, volcanoes gradually coughed up a new atmosphere, filling the air with carbon dioxide, water, and nitrogen. Over the next billion years, the earliest bacterial life consumed that carbon dioxide and, in exchange, released methane and oxygen into the atmosphere. Earth also developed a magnetic field, which helped protect it from the Sun, allowing our atmosphere to transform into the oxygen- and nitrogen-rich air we breathe today.

“We were lucky that Earth’s atmosphere survived the terrible times,” said Vladimir Airapetian, a senior Goddard heliophysicist and astrobiologist who studies how space weather affects the habitability of terrestrial planets. Airapetian worked with Saxena and Killen on the early Sun study.

Artist's conception of Early Earth

An artistic conception of the early Earth, showing a surface pummeled by large impact, resulting in extrusion of deep-seated magma onto the surface.Credits: Simone MarchiEarly Earth

Had our Sun been a fast rotator, it would have erupted with super flares 10 times stronger than any in recorded history, at least 10 times a day. Even Earth’s magnetic field wouldn’t have been enough to protect it. The Sun’s blasts would have decimated the atmosphere, reducing air pressure so much that Earth wouldn’t retain liquid water. “It could have been a much harsher environment,” Saxena noted.

But the Sun rotated at an ideal pace for Earth, which thrived under the early star. Venus and Mars weren’t so lucky. Venus was once covered in water oceans and may have been habitable. But due to many factors, including solar activity and the lack of an internally generated magnetic field, Venus lost its hydrogen — a critical component of water. As a result, its oceans evaporated within its first 600 million years, according to estimates. The planet’s atmosphere became thick with carbon dioxide, a heavy molecule that’s harder to blow away. These forces led to a runaway greenhouse effect that keeps Venus a sizzling 864 degrees Fahrenheit (462 degrees Celsius), far too hot for life.

Mars, farther from the Sun than Earth is, would seem to be safer from stellar outbursts. Yet, it had less protection than did Earth. Due partly to the Red Planet’s weak magnetic field and low gravity, the early Sun gradually was able to blow away its air and water. By about 3.7 billion years ago, the Martian atmosphere had become so thin that liquid water immediately evaporated into space. (Water still exists on the planet, frozen in the polar caps and in the soil.)

After influencing the course for life (or lack thereof) on the inner planets, the aging Sun gradually slowed its pace and continues to do so. Today, it revolves once every 27 days, three times slower than it did in its infancy. The slower spin renders it much less active, though the Sun still has violent outbursts occasionally.

Exploring the Moon, Witness of Solar System Evolution 

To learn about the early Sun, Saxena said, you need to look no further than the Moon, one of the most well-preserved artifacts from the young solar system.  

“The reason the Moon ends up being a really useful calibrator and window into the past is that it has no annoying atmosphere and no plate tectonics resurfacing the crust,” he said. “So as a result, you can say, ‘Hey, if solar particles or anything else hit it, the Moon’s soil should show evidence of that.’”

Visualization of the Moon’s permanently shadowed regions, or PSRs, using images taken by NASA’s Lunar Reconnaissance Orbiter. PSRs are places on the Moon that haven’t seen the Sun in millions, or even billions, of years. While the Earth’s tilted axis allows sunlight to fall everywhere on its surface, even at the poles, for at least part of the year, the Moon’s tilt relative to the Sun is only 1.6°, not enough to get sunlight into some deep craters near the lunar north and south poles. PSRs are therefore some of the coldest, darkest places in the solar system.Credits: NASA Goddard/Ernie WrightMore information

Apollo samples and lunar meteorites are a great starting point for probing the early solar system, but they are only small pieces in a large and mysterious puzzle. The samples are from a small region near the lunar equator, and scientists can’t tell with complete certainty where on the Moon the meteorites came from, which makes it hard to place them into geological context. 

Since the South Pole is home to the permanently shadowed craters where we expect to find the best-preserved material on the Moon, including frozen water, NASA is aiming to send a human expedition to the region by 2024.  

If astronauts can get samples of lunar soil from the Moon’s southernmost region, it could offer more physical evidence of the baby Sun’s rotation rate, said Airapetian, who suspects that solar particles would have been deflected by the Moon’s erstwhile magnetic field 4 billion years ago and deposited at the poles: “So you would expect — though we’ve never looked at it — that the chemistry of that part of the Moon, the one exposed to the young Sun, would be much more altered than the equatorial regions. So there’s a lot of science to be done there.”

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June 19, 2019 2:24 am

Very interesting. Can we ever hope to terra form Mars back to having a
atmosphere ? As for Venus, that would I think be a much harder nut to crack.


Reply to  Michael
June 19, 2019 6:57 am

Perhaps somehow shading it enough so that the atmosphere can cool enough for the water to precipitate out.

Reply to  MarkW
June 20, 2019 2:23 pm

Venus has very, very little water in its atmosphere, and probably also its crust.

a happy little debunker
June 19, 2019 2:54 am

Without earth’s spinning core, life would never have existed on this rock, due to the protection due to our enhanced magnetic fields

Current thoughts are that this spinning core was as a result of the mentioned pre-historic collision, that resulted in the formation of the binary system that includes the earth and the moon.

Without this moon exerting it’s influence over the earth, life would also likely never have developed.

So when they say it was ‘aliens’ – think about how unlikely that life similar to Earth’s would have evolved in anything but similar circumstances.

Then think about the likelihood that any alien culture developed in a time frame to correspond with sentient life on Earth.

We are alone – get used to it!

Reply to  a happy little debunker
June 19, 2019 6:27 am

Yeah — when you really think about it – we may very well be alone in many thousands of galaxies and completely cut off from any other intelligent species. I hope we make a generally intelligent AI that can live on after we are gone so that it can keep the spark of intelligence alive as the universe spins down.

John Tillman
Reply to  xenomoly
June 19, 2019 7:55 am

Humanity might evolve into different species rather than go extinct, especially if we colonize the galaxy, which we could do over the next 100,000 years, Our species or subspecies is only about 200,000 years old. An average duration for animal species is about two million years.

Humans also now have the ability to control our own evolution, although we are still subjecct to natural evolutionary processes, too. Indeed, thanks to our expanding population, we’ve been evolving quite rapidly since the invention of agriculture.

Joel O'Bryan
Reply to  John Tillman
June 19, 2019 9:39 am

Our now ability for direct germ-line genetic manipulation (CRISPR/Cas, etc) will likely accelerate evolution in ways we can’t imagine at this time.

Plus the Left was long ago a stauch supporter of eugenics and racial purity. Those tendencies of the Leftist-elitist mindset will likely come into vogue again in the near future. That is most certainly true if they can achieve a dominate global political systems with their socialist-neoMarxist ideology using their climate Trojan Horse.

John Tillman
Reply to  Joel O'Bryan
June 19, 2019 10:33 am

Yup. In future, everyone will be not only above average, but superhuman.

Reply to  a happy little debunker
June 19, 2019 6:59 am

Where did you hear that the Earth’s core is spinning at a rate different from the rest of the planet?

John Tillman
Reply to  MarkW
June 19, 2019 8:00 am


By the mid-20th century, geologists had gathered further evidence for this (westerly) drift (of Earth’s magnetic field) and had determined that the westerly rotation of the magnetic field exerts a force on the liquid outer core— composed of a molten mix of iron and nickel — that causes it to rotate in a westerly direction. Decades later, geophysicists used deep seismic data to determine that the inner core — a solid iron-nickel alloy that is about the size of the moon — rotates in an easterly direction, at a greater speed than the rotation of the Earth itself.

Reply to  MarkW
June 19, 2019 4:50 pm

I wondered that too; but according to this study
the inner core rotates about 2/3 second per day faster than the rest of the planet. At that rate, it takes it around 400 years to lap the rest of us.

Of course, that 2013 study is only two years newer than a 2011 study that claimed the core only rotated at one degree faster per million years: https://www.sciencedaily.com/releases/2011/02/110220142817.htm.

Guess we should ask Arne Saknussemm. (I’d say we could ask Otto Lidenbrock or his nephew Axel or Hans Bjelke, but they didn’t make it that far.)

John Tillman
Reply to  a happy little debunker
June 19, 2019 7:48 am

We might be alone in the Milky Way, but other galaxies are liable to contain nuclear physicists of some kind. Our own probably also has many worlds with microbes, if not multicellular organisms.

Wherever the right conditions exist, life is probably inevitable. Those conditions aren’t too demanding: a liquid medium and an energy source, with, for life as we know it, the abundant elements hydrogen, carbon, oxygen and nitrogen, plus phosphorus and certain other less common atoms. But even here on earth, where microbes arose rapidly, it took about another three and a half billion years for animals (protosponges) to evolve (from colonial choanoflagellate unicells). Microbes are still the dominant lifeforms. We swim in a sea of microbes, around, on and in us. We can’t live without them, but they also naturally can kill us.

Reply to  John Tillman
June 19, 2019 10:23 am

If the conditions are not too demanding for the creation of life, why has it not been done in the lab? People claim it is because Earth had hundreds of millions of years for it to happen, but that’s a flawed theory. Those eons were required just to randomly bring about the perfect conditions. Those are the same conditions that are non-randomly produced in the lab, thus eliminating the need for those eons.

Further, in nature, the randomly produced perfect environment will not last long – just hours at a time if you are depending on solar flares. If not dependent upon solar events, those conditions would still be subjected to constantly occuring natural events (current, rain, wind, tide, sunset, storm, etc) capable of destroying the random meeting of chemicals and energies necessary for the creation of life, or adding an element to the mix that would poison the possibility of creation. Again, perfect conditions in the lab, left so for long periods, have resulted in nothing.

I think there is a ‘missing ingredient’ for the creation of life, and until it is identified, we can make no realistic approximation as to how common life in the universe is.

John Tillman
Reply to  jtom
June 19, 2019 11:29 am

Abiogenesis is just chemistry. No missing ingredients need apply. It has been known for almost two centuries that biochemistry is simply organic, ie carbon, chemistry.


Scientists have not been working on creating life in the lab for very long or in very many places, but strides have been made in recent years. Researchers predict success by 2030 or thereabouts:


Lipid bilayers for simple protocellular membranes form and divide naturally, as do the monomer precursors of biopolymers. Indeed, even oligomers of nucleic acids spontaneously self-assemble, as in the water pockets in ice. The trick is getting the chains to keep growing, ie polymerize, before they’re broken up. Recent experiments suggest that peptides, ie short chains of amino acid monomers, the precursors of proteins, and nucleic acid oligomers might have catalyzed each others’ polymerization and replication, much as polymeric protein enzymes and RNA and DNA do today.

It’s hard to recreate in a little lab the conditions on primordial Earth, with trillions of reactions going on per second for hundreds of millions of years. There is also the possibility that life first arose in space, billions of years before the solar system formed, or in it but before the planets coalesced. Asteroids even today contain water.

If life developed independently on Earth, then it now appears that a better candidate locale is terrestrial surface volcanic pools with wet and dry cycles rather than around deep sea thermal vents. But in any case, some method of concentrating the monomers and oligomers is required for them to polymerize. Just floating in an organic chemical soup in the open ocean probably wouldn’t work.

Evidence has emerged that life appeared here remarkably rapidly, perhaps as early as 4.2 Ga. That’s nearly as soon as it could, although that still leaves 300 million years for precursor compounds to form from simpler molecules. But meteorites contain amino acids, sugars, lipids and even nucleobases.


Reply to  John Tillman
June 19, 2019 4:48 pm

There were on-going lab experiments when I was a child, over sixty years sgo. They were not new. Success was always touted as being within a couple of decades, and many were not in your ‘little labs’. Sure, many chemical reactions were taking place on primordial earth, almost all of them would have been counter to the environment required to produce life. All those processes must be absent from the environment that did produce life, diminishing the likelihood of creating life.

Regardless of the “successes”, and what different processes can do what, the very simple fact remains; there has been no human creation of life, even in its simplest forms, and no life found other than on Earth.

Sure, biochemistry is just organic chemistry – so what’s the problem creating life? Of course there is a missing element. If there weren’t we would be churning out new life with ease. We…do…not…know…what must come together to create life. Oh sure, we know some, we may know most, but we clearly don’t know the entire process because we can’t do it. Despite that, people don’t hesitate making the ludicrous claim that if the elements needed for life exists, then life must exist. Where is the evidence for that? There is a huge difference between the natural creation of organic compounds and life.

Until you can produce life, or find it elsewhere off the planet, it is not possible to estimate how much life there is in the universe. So if you know how to create life, do it. Otherwise, you must admit that we cannot conclude anything about the possible existence of other life in the universe until we find it.

John Tillman
Reply to  John Tillman
June 19, 2019 5:29 pm

There were not lab experiemnts to create life sixty years ago. There was a successful attempt to make amino acids in the 1950s. But now we know that they abound in interplanetary space.

So far we know that there is a 100% certainty of life on a planet with liquid water on its surface, energy sources and the chemical building blocks of life.

No one 20 years ago would have predicted life in the lab. Please state where you got the idea that anyone did. Famed origin of life researcher Leslie Orgel died in 2007 thinking that it was perhaps an unsolvable mystery. The great strides of the past decade have dispelled that pessimistic notion, thanks in large part to more money and the interest in the subject of great scientists, including Nobel Prize-winners such as Harvard’s Jack Szostak.

John Tillman
Reply to  John Tillman
June 19, 2019 5:55 pm

I should add that amino acid creation experiments in the ’50s assumed an incorrect composition for the Hadean and Archaean atmospheres of Earth. But already by

Of course there is no missing element. There is only chemistry and physics. The problems are being solved. It’s simply an issue of chemical engineering.

Already in 1961, Joan Oro found that amino acids could be made from hydrogen cyanide (HCN) and ammonia in a water solution simply by heating. His experiment also produced a large amount of adenine, the most important nucleobase, vital not just in RNA and DNA, but in the energy cycle of all living things, in AMP and ATP.

John Tillman
Reply to  John Tillman
June 19, 2019 6:10 pm

I should add that only in the last 15 years or so, ie in this century, has science been able to reconstruct the late Hadean atmosphere with any degree of certainty.

John Tillman
Reply to  John Tillman
June 19, 2019 8:01 pm

I’d also greatly appreciate your psoting those scientists who predicted life in the lab within ten years before about 2015. I don’t know of any, but I easily could have missed them.


Reply to  a happy little debunker
June 19, 2019 9:27 am

So you think that life could not evolve underground?
I believe there is now more biomass underground than on the surface.

Joel O'Bryan
Reply to  joel
June 19, 2019 10:08 am

strict definitions matter here.

John Tillman
Reply to  joel
June 19, 2019 10:31 am
John Collis
June 19, 2019 3:34 am

The Earth also has tectonic plates which other terrestrial planets don’t appear to have.
The Earth’s satellite is significantly larger than any other in the solar system compared with the size of the primary, this means that the Earth is more stable in its rotation.
Venus’ conditions are more to do with the tidal forces of the sun, the planet sees the sunrise in the west and sunset in the east, with a rotational period greater than its orbital period. https://m.youtube.com/watch?v=Y_fiFzTceZc&t=321s

Joel O'Bryan
Reply to  John Collis
June 19, 2019 9:43 am

Mars has undergone large obliquity swings as well. It’s last big obliquity swing to almost 45 deg likely melted the ice at its poles and gave a temporary flushing of water and CO2, probably 5 million or so years ago. And that will continue to happen, becasue Mars does not have a large Moon to stabilize it like Earth does.

June 19, 2019 3:46 am

Can ANY publication mention Venus and not also say “runaway greenhouse effect”?

Carbon Bigfoot
Reply to  Voltron
June 19, 2019 5:51 am

“So there’s a lot of science to be done there.” Or was that the moon?—got to those cards and letters coming and grants at the trough.

Patrick MJD
Reply to  Voltron
June 19, 2019 6:02 am

Yeah exactly. There is no “runaway GHE” on Venus. Its perfectly normal *FOR* Venus.

Reply to  Voltron
June 19, 2019 4:26 pm

Venus is (on the average) 0.723 AU from the Sun; the Earth is (by definition, and on the average) 1.0 AU from the Sun. Venus therefore gets (1/.723)^2 = 1.91 times as much light from the Sun. I don’t know how much hotter than Earth it would be if it had an Earth-like atmosphere, but I would imagine quite a bit hotter. In other words, its distance from the Sun must surely account for a good deal of its hotter temp.

Reply to  Voltron
June 19, 2019 5:54 pm

Yeah. The fact its closer to the sun and has atmospheric pressure 90 times Earths is the main reason why the temperature is so hot. Corrupted Science

June 19, 2019 5:20 am

‘Using sophisticated computer models’

Stopped reading here. ‘Sophisticated’ is subjective. Subjective statements poison science reports. It leaves one wondering how much of the rest of the report is subjective.

Alan Tomalty
Reply to  Gamecock
June 19, 2019 10:04 am

“But due to many factors, including solar activity and the lack of an internally generated magnetic field, Venus lost its hydrogen”


Reply to  Alan Tomalty
June 19, 2019 4:33 pm

The spin rate is claimed to affect the solar activity, which is the first of the factors they name. So yes, the spin rate of the Sun is relevant.

You can read about spin (rotation) rates of stars, and how it’s measured, here: https://www.centauri-dreams.org/2015/01/13/a-stellar-correlation-spin-and-age/

Reply to  Alan Tomalty
June 19, 2019 4:50 pm

Fake science is apparently more profitable than fake news.

Ryan Welch
June 19, 2019 5:34 am

Without an atmospheric pressure about 90 times that of earth (9.0 MPa) Venus would not have a temperature of 457 °C (855 °F). Yes greenhouse warming is part of the equation, but atmospheric content has much less a role than atmospheric pressure.

Paul Penrose
Reply to  Ryan Welch
June 19, 2019 9:46 am

Also, Venus receives more energy from the sun (being closer, duh) than the Earth. Whenever you hear somebody credit the “greenhouse effect” for Venus’ high surface temperature, you know they are either ignorant of basic physics, or are lying to you.

June 19, 2019 5:45 am

Awwww baby sun.
Naughty naughty baby sun!

June 19, 2019 5:50 am

show that the early Sun rotated slower than 50% of baby stars.

Another aspect of our solar system’s Goldilocks Effect?

Tom Abbott
Reply to  beng135
June 19, 2019 7:19 am

Yes, we will have to take the star’s rotation rate into consideration when looking at whether life as we know it might originate in that solar system.

We need bigger telescopes! 🙂

Reply to  Tom Abbott
June 19, 2019 10:33 am

James Webb in 2021….. Gold-coated mirrors & chilled down to be a combination IR/visible light telescope.

PS The list of fortunate occurrences in our solar system for development of long-lasting, complex life is very long & seems to continue getting longer….

John Tillman
Reply to  beng135
June 19, 2019 11:01 am

We are also discovering that even multicellular organisms, to include animals like nematodes and tardigrades, can survive and thrive in extremes of temperature and pressure. Microbes, even more so.

Arthur G Foster
June 19, 2019 6:06 am

I presume the physics of this spin slow down have been worked out (?) With a tide measured in millimeters, the sun had to transfer its angular momentum to Jupiter, etc.? How far may the planets be presumed to have moved away from the sun? –AGF

Reply to  Arthur G Foster
June 19, 2019 7:32 am

The conventional explanation is that the momentum is transferred to the solar wind, not the planets:


Arthur G Foster
Reply to  tty
June 19, 2019 10:07 am


June 19, 2019 6:47 am

The sun has a cyclical pattern of strong flares. They were sent to the moon to find glass beads . Mars has the same glass beads. Eject from the sun.
Earth’s ocean’ levels provide evidence w/ man made structures founder hundreds of meters below…!
Think of a renewal cycle.
Only fragments of past civilization found, demonstrating out of place technology.


David L Hagen
June 19, 2019 6:50 am

Another strong parameter for the Anthropic Principle.

Gonzalez, G., 2005. Habitable zones in the Universe. Origins of life and evolution of biospheres, 35(6), pp.555-606.

Abstract. Habitability varies dramatically with location and time in the universe. This was recognized centuries ago, but it was only in the last few decades that astronomers began to systematize the study of habitability. The introduction of the concept of the habitable zone was key to progress in this area. The habitable zone concept was first applied to the space around a star, now called the Circumstellar Habitable Zone. Recently, other, vastly broader, habitable zones have been proposed. We review the historical development of the concept of habitable zones and the present state of the research. We also suggest ways to make progress on each of the habitable zones and to unify them into a single concept encompassing the entire universe.

See further: Anthropic Principle at Uncommon Descent

June 19, 2019 6:55 am

“Venus lost its hydrogen — a critical component of water. As a result, its oceans evaporated within its first 600 million years, according to estimates. ”

How exactly does the loss of elemental hydrogen result in water evaporating????

Everything I’ve read up till now has concluded that Venus never cooled down enough for oceans to form in the first place.

Reply to  MarkW
June 19, 2019 1:29 pm

No, it is theoretically possible that Venus was habitable early in its history.

Water loss is by water breaking down into hydrogen and oxygen in the exosphere and the hydrogen atoms escaping into space while the oxygen ends up bound in oxides.

June 19, 2019 7:14 am

I hate these silly “science-for-the-idiot-generation” press releases. Here is the actual paper:


A lot less dramatic, and without the CAGW genuflections.

Tom Abbott
June 19, 2019 7:27 am

A very interesting study. I learned some things.

I saw a report yesterday where several Earth-like planets have been discovered around 12 lightyears away. Now we are going to have to know what their star’s rotation rate is. Maybe astronomers can spot some sunspots from that distance.

Of course, we have to be careful when we hear the description “Earth-like” as that might mean a rocky planet with two or three or more times the gravity of the Earth, so in those cases, they are hardly Earth-like, other than in their rocky composition

Joel O'Bryan
June 19, 2019 8:49 am

finding analogs our our sun and solar system has been difficult and so far not one out of thousands of candidates.

We can find lots of G class stars at ~5,800 K surface temperature, but their metalicity is low (that matters immensely), or they are in binary or trinary systems, or they have observed flare activity of the type described by fast rotators.
Or they have hot close Jupiters, initially formed out beyond the frost line, that would have tidally disrupted any inner rocky planets, either sending them into the cold interstellar abyss or gravitationally-tidally turning them into rubble like the asteroid belt.

And then there’s the exceeding rarity of our Moon, basically we’re a binary planet. With the tidal forces from that likely helping start and maintain earthly tectonics.

Goldilocks indeed.

Mark Broderick
June 19, 2019 9:00 am

“NASA reveals new image of dwarf planet ‘like nothing that humanity has ever seen before’


“In addition to being a dwarf planet, Ceres is also the largest known asteroid, with a diameter approaching 600 miles. “

Tom Abbott
Reply to  Mark Broderick
June 19, 2019 5:19 pm

“In addition to being a dwarf planet, Ceres is also the largest known asteroid, with a diameter approaching 600 miles. “

I read a little factoid today that said scientists had connected meteorites that landed in Turkey with a collision that had taken place on Ceres! That’s some pretty good detective work!

June 19, 2019 9:27 am

When you consider the violent beginnings of our planet maybe we are the only life in the universe. A lot of odds-beating things happened, in just the right proportions and time scale, to create life on Earth. It’s mystical when you think about it. You certainly could have made a lot of money in Vegas by betting on it.

June 19, 2019 9:46 am

Does the rotational speed of the Sun affect the magnetic activity of the Sun?
How does the rotational speed of the Sun change depending on the location of the center of gravity of the Solar System?

Joel O'Bryan
Reply to  ren
June 19, 2019 10:15 am

when you discuss various solar rotational velocities, you have to specify layer/depth, and latitude for the Convective Zone.
They all vary.
It is what makes studying the internal sun with models and helioseismic studies so complex. And with complexity in natural systems, emergent behaviors arise that cannot be predicted from first principles.

June 20, 2019 5:41 am

Who would have believed it, NASA going to the moon in 5 years time. Am I dreaming or what?

June 20, 2019 9:04 am

“Using sophisticated computer models…”

No need to continue reading.

jack okie
June 20, 2019 1:04 pm

There is an alternate cosmology that proposes that much of the phenomena we see in the universe is due to plasma, not gravity. I have been looking at this for several years, and to date I’ve seen a lot of derision, ad hominems, and misstatements of the theory, but I have not yet seen it successfully falsified. Here is an article which compares actual laboratory experiments of plasma scarring and machining with features observed throughout the planets and moons of our solar system. Of course, a key question is “Do the lab effects scale up?”.


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