Every star meets the end of its existence as a regular sun at some point. It usually also means the end of segments in orbits around this star planet. Some of them can survive this catastrophe, not only in theory, but knowledge already confirmed through observations
Anyone intrigued by astronomy knows that nothing is 100% certain about it. The opinions we hold at a given moment may depend on our current observational skills, and on the mathematical apparatus we currently have to describe the universe.
Nearly three decades in a universe with planets outside the solar system
Once upon a time, the solar system with its planets was a creature unique to us on a cosmic scale. Exoplanets were discussed only theoretically, until 1992, when Alexander Walshzan discovered disturbances in the pulsation of the pulsar PSR1257 + 12 milliseconds. Analysis of this data confirmed our belief that it was the result of other, smaller planets in orbit. this object. planet. At first, it was believed that there were four such things, but in the end it ended up with three.
Envision one of the best extrasolar systems, Kepler-186
However, the first ever confirmed planetary system was unattractive from the perspective of classical life, in which a pulsar emits deadly X-rays. In addition, the planets assumed the most likely observed shape after the pulsar’s formation, but their existence has led astronomers to discuss the problem of the planet’s survival after the death of their parent star.
Today we know of thousands of planets, both largest and smallest, in tight, looser orbits around regular stars. We also know that our stats depend on our observational skills, so it was only a matter of time until we discovered new things out of our view.
Planets revolve around white dwarfs
In October 2020, a planet was detected orbiting a white dwarf with the symbol WD 1856 + 534. The planet WD 1856 b is a Jupiter-class object, seven times larger than the white dwarf, which is about 18,000 kilometers wide. While it seems silly for a larger object to orbit a smaller one, this is due to the laws of gravity and the fact that a white dwarf contains most of the mass of this system.
Picture of the planet WD 1856 b
This object was observed using the transit method with the TESS space observatory. However, the distance between it and the white dwarf is less than 3 million km, which means that the orbit must have shrunk severely at some point. So we were still waiting to discover a planetary system that would better suit our future.
In the end it worked. Once again, we have a Jupiter-class object (about 40% larger than Jupiter to be exact) orbiting a white dwarf about 60% the mass of the Sun. However, this time it was detected during the subsequent observations of the object MOA-2010-BLG-477L, that is, the phenomenon of microgravity from 2010. Due to the nature of the detection technique, the distance of the system is very long, approximately 6,500 light-years.
Visualization of a Jupiter-like planet orbiting a white dwarf, Photo: WM Keck Observatory / Adam Makarenko
Additional observations of this object confirmed that the central object is a white dwarf, ruling out the possibility of a neutron star or black hole. Most important in this case is the fact that the planet revolves around the white dwarf in a large orbit. At a distance of at least 420 million kilometers. For comparison, the average distance of Jupiter from the Sun is 778 million km.
Observations of planets in orbits of white dwarfs, which are clearly remnants of an earlier planetary system, support theories and computer models that indicate that there are planets around more than half of the white dwarfs in the galaxy.
There is hope of resorting to one of Jupiter’s moons or beyond
Of course, not every planet in a particular planetary system will survive the end of the main phase in the life of the parent star less than 8 times the mass of the Sun, that is, left over by white dwarfs. In the case of our planetary system, the rocky planets closest to Jupiter are unlikely to survive the stage when the Sun swells to a gigantic size. They will devour and destroy. Even Mars would not be a safe haven.
However, Jupiter is not only very far from the Sun, it is also so massive that even rejecting matter before the formation of a white dwarf would not prevent its existence. Yes, much of the matter in its outer layers will fold into the pulsating giant sun, and when it resurrects its last breath as a star, but most of the gas giant’s mass will remain as a planet.
The remaining gas giants in our solar system, which are farther from Jupiter than the sun, also have a chance. And if these planets survive, so can the moons orbiting them.
Astronomers suppose that one can then imagine an advanced Earth civilization that in the future, in order to protect itself from the end of the Sun, not only sets out to conquer the distant universe, but also travels to the moons of the giant planets. The latter perspective appears to be possible long before the Sun reaches the giant stage. The existence of Earth civilization at such a distant point, within a few billion years, when the Sun begins to die, is in turn a matter of debate.
Then what when we reach the end of time?
If you are interested in thinking about the distant future of the entire universe, the animation below may be of interest. It is true that it is long, as long as the universe probably exists, but it also stimulates interesting contemplation.
Source: Nature, inf. Private, Photo: WM Keck Observatory / Adam Makarenko
