The Universe is very diverse, and in it there are galaxies, stars, planets, and many more different objects. And they all have different ages, just like people. For example, the age of the Solar System, the Sun itself and all the planets is the same - approximately 4.5 billion years, because they were formed at the same time from the same gas and dust cloud. But what is the oldest planet known? After all, there are probably older ones.
Meet Methuselah - the most ancient planet
Thousands of exoplanets are now known, located around a variety of stars. And among them there is one that is very old, even by cosmic standards. The name of this centenarian is Methuselah, or PSR B1620-26b.
This planet is located in the constellation Scorpio, unimaginably far from us - 12,400 light years away. Methuselah is a huge planet. Its mass is 2.5 times the mass, but in size it is slightly smaller.
Interestingly, it is located in the famous globular cluster M4. All the stars in this cluster formed at the same time, approximately 12.7 billion years ago, so the age of the planet is the same. Planet Methuselah is three times older than our Earth! And it appeared when the Universe itself was still very young!
This is what the most ancient planet Methuselah looks like in the Space Engine program.Then, perhaps, a certain star just appeared, lived out its life, exploded, and after another billions of years the Solar System began to form from a cloud of gas. And the planet Methuselah was already old then!
Even more curious is the system in which this most ancient planet known to us “lives.” The fact is that this is a double system, one of the stars of which is a white dwarf, that is, a star that has long completed its life path and is at the last stage of its evolution.
But another component of the system is even more interesting - it is a pulsar, which rotates at a breakneck speed of 100 revolutions per second. The distance between the pulsar and the dwarf is only 1 astronomical unit, the same as from the Earth to the Sun.
And now, at a distance of 23 astronomical units from this double system, the planet Methuselah floats in its orbit, looking at the remnants of its once bright and majestic luminaries. Perhaps they once gave life, but now they give only deadly radiation. For comparison, the distance from the planet to them is approximately the same as from the Sun to Uranus.
Although there are different hypotheses here. Pulsars appear after supernova explosions, which destroy everything around them, including planets. So, most likely, Methuselah’s home star is a white dwarf, and the pulsar joined the system later, it is believed that this happened about 10 billion years ago. Moreover, in a globular cluster the stars are located much closer together, and the formation of systems from neighbors there will not surprise anyone.
The star that has now become a white dwarf is the home star of Methuselah. When it turned into a red giant and filled its Roche lobe, its material began to flow onto the pulsar, which began to rotate faster and faster. In the end, it all ended with the red giant becoming unstable, shedding its matter, and shrinking to a white dwarf.
As we can see, many disasters have occurred in this ancient system, and more are expected. The fact is that it is moving towards the center of a globular cluster, and there the density of stars is very high. Therefore, the system will experience a lot of gravitational influence, maybe it will enter another system, or will be destroyed. Or a planet rotating in a distant orbit will be captured by another star. In any case, it's definitely not boring there.
She has already been dubbed “Methuselah” - in honor of the biblical patriarch who lived 969 years. This is an incredible age for a person, but 13 billion years also seemed an impossible age for the planet. However, thanks to Hubble, such a planet was discovered.
The first question that arises when you read the phrase “13 billion years” is whether this is a mistake? It arises because the appearance of any planet less than a billion years after the Big Bang seems completely incredible. At least from the point of view of the prevailing theory on the history and evolution of the Universe.
For this theory says: there were no heavy elements in the first generation of stars - only hydrogen and a little helium. Then, as such stars consumed their gaseous “fuel,” they exploded, and their remains, scattering in all directions, fell on the surface of neighboring stars (which, at the very beginning of the Universe, were naturally much closer to each other, than now). As a result of thermonuclear fusion reactions, new elements were formed. More severe.
The age of the solar system with its planets, including Earth, is estimated by scientists to be approximately 4.5 billion years. Most known exoplanets (that is, planets discovered near other stars) are approximately the same age.
This gave scientists reason to say that this is the time threshold for the formation of planets. Planets containing heavy elements.
Then how can it be that the planet arose 13 billion years ago, if, according to the latest data, the Universe itself is 13.7+/-0.2 billion years old?
Image of the planet made by NASA artists.
However, if you think about it, theoretically nothing contradicts the possibility of the appearance of such a planet. NASA has found that the first stars began to appear in the Universe 200 million years after the Big Bang.
Since at that time the stars were much closer to each other than now, for obvious reasons, the formation of heavy elements could it's quite happening lively pace.
In addition, you need to keep in mind where exactly this planet is located. We are talking about the globular cluster M4, consisting mainly of ancient stars belonging to the first generation. This cluster is located 5,600 light years from the Solar System, and for an earthly observer is located in the constellation Scorpio.
However, it is known about such accumulations that there are very few heavy elements there. Precisely because the stars that make it up are too ancient.
This is precisely why, by the way, most astronomers did not believe that planets could exist in globular clusters.
In 1988, the pulsar PSR B1620-26 was discovered rotating at 100 revolutions per second in M4. Soon a white dwarf was discovered near it, and it became obvious that the system was double: the pulsar and the dwarf revolved around each other with a period of once every Earth year. It was precisely by the gravitational influence on the pulsar that the white dwarf was calculated.
However, it was later discovered that the pulsar was influenced by another cosmic object. Someone came up with the idea of a planet. They waved their hands at him, since they were talking about a spherical cluster. But the debate continued: throughout the 1990s, astronomers tried to understand what it was. There were three hypotheses: a planet, a brown dwarf (that is, an almost completely burnt-out star), or some very tiny “ordinary” star with a very insignificant mass.
The problem was that the mass of the white dwarf could not be determined then.
Hubble came to the rescue. The data obtained by this telescope eventually allowed us to calculate the exact mass and temperature of the white dwarf (as well as its color). By determining the dwarf's mass and comparing it with changes in the radio signals coming from the pulsar, astronomers calculated the inclination of its orbit relative to Earth.
And having determined the inclination of the white dwarf’s orbit, scientists were able to determine the inclination of the orbit of the proposed planet and calculate its exact mass.
Two and a half masses of Jupiter is too small for a star, and even for a brown dwarf. Accordingly, the planet is the only remaining option.
Scientists suggest that it is a gas giant in which heavy elements are present in very small quantities - for the reasons stated above.
Photo of the globular cluster M4 (Messier 4).
Methuselah was formed near a young star, similar in its properties to the young, again, Sun.
Somehow, this planet survived everything that could be survived - frantic ultraviolet radiation, radiation from nearby supernovae, and shock waves from their explosions - everything that accompanied the processes of the death of old stars and the formation of new stars in what later will be called the M4 globular cluster.
The planet and its star suddenly approached the pulsar and found themselves trapped in it. Perhaps the pulsar previously had its own satellite, which was knocked out into outer space.
The star around which Methuselah orbits swelled over time, becoming a red giant, and then shrunk to a white dwarf, in effect accelerating the pulsar's rotation.
Methuselah continued to regularly rotate around both stars at a distance approximately equal to the distance from the Sun to Uranus.
The fact of the existence of such a planet at least suggests that there may be much more planets in the Universe than previously thought. On the other hand, Methuselah is supposedly a gas giant. A denser and more Earth-like planet in M4 simply would not have worked out... On the other hand, the theory stated that in star clusters where there are few heavy elements, there cannot be planets at all.
It seems that the only thing in the Universe can't be- so this is something impossible.
Our Universe is full of amazing and inexplicable things. For example, today scientists have discovered hypervelocity stars that do not fall and are not meteorites, giant clouds of dust with the aroma of raspberries or smelling of rum. Astronomers have also discovered many interesting planets outside our solar system.
Osiris or HD 209458 b is an exoplanet near the star HD 209458 in the constellation Pegasus, located at a distance of more than 150 light years from Earth. HD 209458 b is one of the most studied exoplanets outside the Solar System. The radius of Osiris is close to 100,000 kilometers (1.4 times the radius of Jupiter), while the mass is only 0.7 that of Jupiter (approximately 1.3 1024 tons). The distance of the planet to the parent star is very small - only six million kilometers, so the period of its revolution around its star is close to 3 days.
Scientists have discovered a storm on the planet. It is assumed that there is a wind blowing from carbon monoxide (CO). The wind speed is approximately 2 km/s, or 7 thousand km/h (with possible variations from 5 to 10 thousand km/h). This means that the star quite strongly heats up the exoplanet located from it at a distance of only 1/8 of the distance between Mercury and the Sun, and the temperature of its surface facing the star reaches 1000°C. The other side, which never turns towards the star, is much cooler. The large temperature difference causes strong winds.
Astronomers were able to establish that Osiris is a comet planet, that is, a strong flow of gases constantly flows from it, which is blown away from the planet by the radiation of the star. At the current rate of evaporation, it is predicted that it will be completely destroyed within a trillion years. A study of the plume showed that the planet evaporates entirely - both light and heavy elements leave it.
The scientific name of the rock shower planet is COROT-7 b (previously it was called COROT-Exo-7 b). This mysterious planet is located in the constellation Monoceros at a distance of about 489 light years from Earth and is the first rocky planet discovered outside the solar system. Scientists speculate that COROT-7 b may be the rocky remnant of a gas giant the size of Saturn that was "evaporated" by the star to its core.
Scientists have found that on the illuminated side of the planet there is a vast lava ocean, which forms at a temperature of about +2500-2600°C. This is higher than the melting point of most known minerals. The planet's atmosphere consists mainly of evaporated rock, and deposits rocky sediments on the dark side and the light side. The planet is probably always facing the star with one side.
Conditions on the illuminated and unlit side of the planet are very different. While the illuminated side is a churning ocean in continuous convection, the unlit side is likely covered by a huge layer of ordinary water ice.
The planet Methuselah - PSR 1620-26 b, located in the constellation Scorpius at a distance of 12,400 light years from Earth, is one of the oldest exoplanets currently known. According to some estimates, its age is about 12.7 billion years. The planet Methuselah has a mass 2.5 times greater than Jupiter and orbits an unusual binary system, both components of which are burnt-out stars that have long completed their active evolutionary phase: a pulsar (B1620−26 A) and a white dwarf (PSR B1620−26 B). In addition to this, the system itself is located in the densely populated core of the globular star cluster M4.
A pulsar is a neutron star that rotates 100 times per second around its axis, emitting strictly periodic pulses in the radio range. The mass of its companion, a white dwarf, which manifests itself as a periodic violation of the accuracy of the “ticking” of the pulsar, is 3 times less than the Sun. The stars revolve around a common center of mass at a distance of 1 astronomical unit from each other. A full rotation occurs every 6 months.
Most likely, the planet Methuselah is a gas giant without a solid surface, like Earth. The exoplanet completes a full revolution around the binary star in 100 years, being located at a distance of about 3.4 billion kilometers from it, which is slightly greater than the distance between Uranus and the Sun. Born very early in the history of the Universe, PSR 1620-26 b appears to be almost devoid of elements such as carbon and oxygen. For this reason, it is very unlikely that there has ever been or is life on it.
Gliese 581c is an exoplanet in the planetary system of the star Gliese 581 at a distance of about 20 light years from our planet. Gliese 581c is the smallest planet ever discovered outside our system, but is 50 percent larger and 5 times more massive than Earth. The planet's rotation period around a star located at a distance of about 11 million kilometers is 13 Earth days. As a result, despite the fact that the star Gliese 581 is almost three times smaller than our Sun, in the sky of the planet its native sun looks 20 times larger than our star.
Although the exoplanet’s orbital parameters are located in the “habitable” zone, the conditions on it are more similar not to those on Earth, as was previously thought, but to the conditions on Venus. Substituting its known parameters into a computer model of the development of this planet, experts came to the conclusion that Gliese 581c, despite its mass, has a powerful atmosphere with a high content of methane and carbon dioxide, and the temperature on the surface reaches +100°C due to the greenhouse effect. So, apparently, there is no liquid water there.
Due to its proximity to the star Gliese 581 c, it is affected by tidal forces and can always be located on one side towards it or rotate in resonance, such as Mercury. Due to the fact that the planet is at the very bottom of the light spectrum we can see, the planet's sky is a hellish red color.
TrES-2b is the blackest planet known as of 2011. It turned out to be blacker than coal, as well as any planet or satellite in our solar system. Measurements showed that TrES-2b reflects less than one percent of incoming sunlight, less than even black acrylic paint or carbon black. Researchers explain that this gas giant lacks bright reflective clouds (like those found on Jupiter and Saturn) due to its very high surface temperature - more than 980°C. This is not surprising, given that the planet and its star are separated by only 4.8 million kilometers.
This planet is located about 760 light years from the solar system. It is almost the same size as Jupiter and orbits a star similar to the Sun. TrES-2b is tidally locked so that one side of the planet always faces the star.
Scientists speculate that TrES-2b's atmosphere likely contains light-absorbing substances, such as sodium and potassium vapor or titanium oxide gas. But even they cannot fully explain the intense blackness of the strange world. However, the planet is not completely pitch black. It is so hot that it produces a faint red light like a burning ember.
HD 106906 b - This gas giant, which is 11 times larger than Jupiter, is located in the constellation of the Southern Cross about 300 light-years from Earth and appeared approximately 13 million years ago. The planet orbits its star at a distance of 97 billion kilometers, which is 22 times the distance between the Sun and Neptune. This is such a great distance that light from the parent star reaches HD 106906 b only after 89 hours, while Earth receives sunlight after 8 minutes.
HD 106906 b is one of the loneliest known planets in the Universe. In addition, according to modern models of the formation of cosmic bodies, a planet cannot form at such a distance from its star, so scientists assume that this lone planet is a failed star.
HAT-P-1 b is an extrasolar planet orbiting the yellow dwarf star ADS 16402 B, located 450 light-years from Earth in the constellation Lizard. It has the largest radius and lowest density of any known exoplanet.
HAT-P-1 b belongs to the class of hot Jupiters and has an orbital period of 4.465 days. Its mass is 60% of the mass of Jupiter, and its density is only 290 ± 30 kg/m³, which is more than three times less than the density of water. It is safe to say that HAT-P-1 is the lightest planet. Most likely, this exoplanet is a gas giant consisting mainly of hydrogen and helium.
A planet with an incredibly huge system of planetary rings
1SWASP J140747.93-394542.6 b or J1407 b for short is a planet that contains approximately 37 rings, each of which is tens of millions of kilometers in diameter. It revolves around a young solar-type star J1407, periodically covering the light of the star with its “sarafan” for a long period of time.
Scientists have not decided whether this planet is a gas giant or a brown dwarf, but it is definitely the only one in the system of its star and is located at a distance of 400 light years from Earth. The ring system of this planet is the first discovered outside the solar system and the largest known at the moment. Its rings are much larger and heavier than those of Saturn.
According to measurements, the radius of these rings is 90 million kilometers, and the total mass is a hundred times the mass of the Moon. For comparison: the radius of Saturn's rings is 80 thousand kilometers, and the mass, according to various estimates, ranges from 1/2000 to 1/650 of the mass of the Moon. If Saturn had similar rings, then we would see them at night from Earth with the naked eye, and this phenomenon would be much brighter than the full moon.
In addition, there is a visible gap between the rings, in which scientists believe a satellite was formed, whose rotation period around J1407b is about two years.
Gliese 436 b is an exoplanet located 33 light years from Earth and located in the constellation Leo. It is comparable in size to Neptune - 4 times larger than Earth and 22 times heavier. The planet orbits its parent star in 2.64 days.
The amazing thing about Gliese 436 b is that it is primarily composed of water, which remains in a solid state at high pressure and a surface temperature of 300°C - “burning ice”. This is due to the enormous gravitational force of the planet, which not only prevents water molecules from evaporating, but also compresses them, turning them into ice.
Gliese 436 b has an atmosphere composed primarily of helium. Observations of Gliese 436 b using the Hubble Space Telescope in the ultraviolet revealed a huge tail of hydrogen trailing behind the planet. The length of the tail reaches 50 times the diameter of the parent star Gliese 436.
55 Cancri e is a planet located in the constellation Cancer at a distance of about 40 light years from Earth. 55 Cancri e is 2 times larger than Earth in size and 8 times larger in mass. Because it is 64 times closer to its star than the Earth is to the Sun, its year lasts only 18 hours, and the surface heats up to 2000°K.
The composition of the exoplanet is dominated by carbon, as well as its modifications - graphite and diamond. In this regard, scientists suggest that 1/3 of the planet consists of diamonds. According to preliminary calculations, their total volume exceeds the size of the Earth, and the cost of the subsoil of 55 Cancri e can be 26.9 nonillion (30 zeros) dollars. For example, the GDP of all countries on Earth is 74 trillion. (12 zeros) dollars.
Yes, many discoveries sound no more realistic than science fiction and turn all scientific ideas upside down. And we can confidently say that the most unusual planets are still waiting to be discovered and will surprise us more than once.
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Long before the birth of the Sun and the Earth, a giant planet was born near one of the Sun-like luminaries of our Galaxy. 13 billion years after these events, the Hubble Space Telescope was able to accurately measure the mass of this ancient exoplanet - also the most distant from us known today. Her story is amazing. The planet has been brought to an extremely unfriendly and inhospitable place: it orbits an unusual binary system, both components of which are burnt stars that have long completed their active evolutionary phase. In addition to this, the system itself is located in the densely populated core of a globular star cluster.
Rice. 1. 5600 light years separate us from the globular cluster M4, and therefore from the found planet. Galactic coordinates of the cluster are L=351° b=+16°. This is somewhere above the Sagittarius arm - the inner arm of the Milky Way relative to ours.
The new data from Hubble caps a decade of intense debate and speculation about the true nature of this ancient world, which majestically and leisurely circles the unusual binary system in a wide orbit, completing one revolution every century. The planet turned out to be 2.5 times heavier than Jupiter. Its very existence serves as eloquent evidence that the birth of the first planets began in the Universe very soon after its birth - already in the first billion years after the Big Bang. This discovery leads astronomers to the conclusion that planets may be a very common phenomenon in space.
Now this planet is located almost at the very core of the old globular cluster M4, which we see in the summer sky in the constellation Scorpius, at a distance of 5600 light years from Earth. As is known, globular clusters are very poor in heavy elements compared to the Solar System, since they were formed in the Universe very early - at a time when elements heavier than helium had not yet had time to “cook” in the “nuclear cauldrons” of stars. For this reason, some astronomers were even inclined to think that globular clusters may not contain planets at all. You probably remember what a powerful argument in favor of this pessimistic point of view was a unique experiment conducted in 1999 with the help of Hubble, during which astronomers specifically searched for “hot Jupiters” in the globular cluster 47 Tucanae and did not find a single one there! The current Hubble discovery suggests that astronomers in 1999 may have simply been looking in slightly the wrong place, and that giant gas planets in more distant orbits may be quite numerous, even in globular clusters.
Says Steinn Sigurdson of Pennsylvania State University: "Our result provides a strong argument that planet formation is a fairly undemanding process that can be achieved with even a small amount of heavy elements. This means that it began very early in the Universe."
"The possible abundance of planets in globular clusters is extremely encouraging," adds Harvey Riche of the University of British Columbia. Speaking about possible abundance, Harvey, of course, relies on the fact that the planet was discovered not just anywhere, but in such a terrible place at first glance, like an orbit around a binary star consisting of a helium white dwarf and... a rapidly rotating neutron stars! Moreover, this entire bunch is located very close to the densely populated core of the cluster, where frequent close encounters with neighboring luminaries threaten fragile planetary systems with complete disintegration.
The history of the discovery of this planet began 15 years ago, in 1988, when a pulsar was discovered in the M4 globular cluster, designated PSR B1620-26. It was a very fast pulsar - the neutron star rotated almost 100 times per second, emitting strictly periodic pulses in the radio range. Almost immediately after its discovery, a companion was found for the pulsar - a white dwarf, which manifested itself as a periodic violation of the accuracy of the pulsar's "ticking". He managed to turn around a neutron star in just six months (more precisely, in 191 days). After some time, astronomers noticed that even taking into account the influence of the white dwarf, there were some problems with the pulsar’s accuracy. Thus, the existence of a third companion was discovered, who orbits at some distance from this unusual pair. It could be a planet, but the option of a brown dwarf, or even a low-mass star, was not excluded (everything depended on the angle of inclination of the third companion’s orbit to the line of sight, which was unknown). This caused heated debate about the nature of the mysterious third companion in the pulsar system PSR B1620-26, which did not subside throughout the 90s of the last century.
Rice. 2.On this small fragment of the circumnuclear region of the globular cluster M4, a circle marks the position of the pulsar PSR B1620-26, invisible in the optical range, known from radio observations. Only two stars fell into this field: a reddish main sequence star lying on its boundary with a mass of about 0.45 M and a definitely blue star with a magnitude of about 24 m, which turned out to be a white dwarf companion to the pulsar.
Sigurdson, Riches and the other co-authors of the discovery were finally able to resolve this dispute by measuring the true mass of the planet in a very ingenious way. They took the best Hubble images from the mid-90s, taken to study white dwarfs in M4. Using them, they were able to find the same white dwarf that orbits the pulsar PSR B1620-26, and estimate its color and temperature. Using evolutionary models calculated by Brad Hansen of the University of California, they estimated the mass of the white dwarf (0.34 ± 0.04 Ms). By comparing it with the observed beats in the periodic signals of the pulsar, they calculated the inclination of the white dwarf's orbit to the line of sight. Together with precise radio data on gravitational disturbances in the motion of the white dwarf and neutron star along the inner orbit, this made it possible to limit the range of possible values of the inclination angle of the outer orbit of the third companion and thereby establish its true mass. Only 2.5±1 Mu! The object turned out to be too tiny to be not only a star, but even a brown dwarf. So it's a planet!
She has 13 billion years behind her. This, you see, is a respectable age. In her youth she must have revolved around her young yellow sun in an orbit similar to Jupiter's. It survived the era of scorching ultraviolet radiation, supernova explosions and the shock waves they caused, which furiously rolled through the young globular cluster like a firestorm in the days of its formation - during the period of rapid star formation. Around the time when the first multicellular organisms appeared on Earth, the planet and its parent star floated into the thick of the M4 circumnuclear region. Apparently, somewhere here they came very close to an old, old pulsar, which remained after the explosion of some supernova from the early days of the cluster’s life and which also had its own companion. During the approach, a gravitational maneuver (exchange of mechanical energy) occurred, as a result of which the pulsar lost its pair forever, but captured our star along with its planet into its orbit. And so this unusual trinity was born, receiving in a new configuration a noticeable recoil impulse, which directed it into the less populated outer parts of the cluster. Soon, as it aged, the planet's mother star swelled into a red giant and, having filled its Roche lobe, began to dump matter onto the pulsar. Together with it, a rotational moment was transmitted to the pulsar, which again spun the neutron star, which had calmed down, to a very high speed, turning it into a so-called millisecond pulsar. Meanwhile, the planet continued its leisurely run in orbit at a distance of about 23 astronomical units from this mated pair (approximately the orbit of Uranus).
What is she like? Most likely, it is a gas giant without a solid surface, like Earth. Born very early in the history of the Universe, it appears to be almost devoid of elements such as carbon and oxygen. For this reason, it is very unlikely that there was ever (or is now) life on it. Even if life arose, for example, somewhere on one of its rocky moons, it would hardly survive the powerful X-ray bursts that accompanied the pulsar's spinning era, when streams of heating gas flowed from the red giant to the neutron star. Sadly, it is difficult to imagine any civilization witnessing and participating in the long and dramatic history of this planet, which began almost as long as time itself.
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A.I. Dyachenko, columnist for the magazine "Zvezdochet"
1). The term exoplanet appeared in astronomy quite recently, at the end of the 20th century. They are called planets discovered around other stars outside the solar system. (