Astronomers find stars that are older than the universe. How is this possible?
After reading the title, you are probably thinking that something is wrong here. But that - the star, the universe, or something else? If you know how stars work, you can take one of them, to study its physical properties, and to know when she was supposed to appear. Stars go through a lot of changes as they age: their radius, luminosity and temperature change as burning fuel. But the life of a star, in general, depends on two properties with which it is born: the mass and metallicity, ie the amount present in it of elements heavier than hydrogen and helium.
The oldest stars, which we found in the universe, virtually untouched and almost 100% composed of hydrogen and helium left over from the Big Bang. They may be 13 billion years old, and the oldest - 14, 5 billion years.
And it's a big problem, because the universe itself only 13, 8 billion years, said Ethan Siegel with Medium.com.
The core of the globular cluster Omega Centauri - one of the most crowded areas of old stars. There can be a star and 12 billion years of age, and the oldest - more than 14 billion years, and it is a problem, because they are older than the universe itself
The stars, who over the universe itself, can not be; otherwise it would have existed long before the Big Bang. But the Big Bang was the source of the known universe, from which came all the matter, energy, neutrinos, photons, antimatter, dark matter and even dark energy. All that is contained in our observable universe began with this event, and all of what we are dealing with today can be traced back to this point. Therefore, the simplest explanation is that the stars could appear before the universe itself, it should be avoided.
It may well be that we have not brought the age of the universe. We extract it from precise measurements of the universe on a large scale. By studying a number of features, including:
- temperature and density defects in the cosmic microwave background, the afterglow of the Big Bang;
- clustering of stars and galaxies at the present time and billions of light years away;
- speed habblova tissue expansion of the universe;
- the history of star formation and galactic evolution;
as well as many other sources, we have a very coherent picture of the universe. It consists of 68% of dark energy, 27% dark matter, 4, 9% of the ordinary matter, at 0, 1% of the neutrinos at 0, 01% of the radiation, and it about 13, 8 billion years. The uncertainty of the age of the universe is in the range of 100 million years, so even though the universe is, of course, can be a hundred million years younger or older than 14, 5 billion years it is unlikely to pick up.
ESA Gaia mission measured the position and properties of hundreds of millions of stars near the galactic center and found the oldest stars known to mankind
There is only one reasonable possibility: perhaps we are wrong to assess the age of stars. We studied in detail the hundreds of millions of stars at different stages of their lives. We know how stars are formed and under what conditions; We know when and how they ignite nuclear fusion; We know how long continuing various synthetic steps and how they are effective; We know how they live and how to die, different types with different masses. In a nutshell, astronomy - serious science, especially if we talk about the stars. In general, the oldest stars have a relatively low mass (less massive than our Sun), contain few metals (elements other than hydrogen and helium), and may be over the galaxy.
you can find very old stars in globular clusters
Many of them are in globular clusters, which are, and that's exactly contain the star of 12 billion or, in rare cases, even for 13 billion years. A generation ago, people argued that these clusters - 14-16 billion years, than to create tensions in established cosmological models, but gradually improving the understanding of stellar evolution has resulted in these figures, in accordance with the norm. We have developed more advanced methods to improve our observational abilities: by measuring not only the carbon, oxygen and iron in these stars, but also with the use of the uranium and thorium decay. We can directly determine the age of the individual stars.
the SDSS J 102915 + 172927- an ancient star in the 4140 light-years away that contains only 1/20 000 of the heavy elements compared to our Sun and should be the age of 13 billion years. This is one of the oldest stars in the Universe
In 2007, we were able to measure the star HE 1523-0901, which amounts to 80% of the mass of the Sun, it contains a total of 0, 1% of the solar iron and is believed to be the age of 13, 2 billion years old, judging by its abundance of radioactive elements. In 2015, near the center of the Milky Way was found nine stars that formed 13, 5 billion years ago, just after 300 million years after the Big Bang. "These stars formed before the Milky Way galaxy was formed around them," said Luis Houvs, sootkryvatel these ancient relics. In fact, one of the nine stars is less than 0, 001% solar iron; this type of stars will be looking for the James Webb Space Telescope when it begins to work in October 2018.
This is a digitized image of the oldest stars in our galaxy. This aging star of HD 140283 is 190 light-years away. The Hubble Space Telescope said her age at 14, 5 billion, plus or minus 800 million years
The most striking of all is the star HD 140283, unofficially nicknamed Methuselah star. It is only 190 light-years from us, and we can measure its brightness, surface temperature and composition; we can also see that it is only beginning to develop in phase subgiant to subsequently become a red giant. These pieces of information allow us to bring well-signposted stars age, and the result is at least cause for concern: 14, 46 billion years. Some properties of the stars, like the iron content of 0, 4% of the sun, they say that the star is old, but the oldest of them all. And in spite of the possible error of 800 million years old, Methuselah still creates a certain conflict between the maximum age of the stars and the age of the universe.
The Milky Way has not changed for billions of years. But as they grow older the most massive stars cease to exist, and the least massive begin to turn into subgiants
Today it is obvious that in the past with this star might have happened something that we do not know today. Maybe she was born more massive and somehow lost its outer layers. Maybe the star swallowed the little matter later, which changed its content of heavy elements, embarrass our observations. Maybe we simply do not understand subgiant phase of stellar evolution in ancient stars with low metallicity. Gradually, we will derive the correct form or calculate the age of the oldest stars.
But if we are right, we have a serious problem. In our universe there can be no stars to be older than the universe itself. Or that something is wrong with the assessment of the age of these stars, or that something is wrong with the assessment of the age of the universe. Or something else, what we do not understand at all. This is a great chance to move the science in a new direction.