Bad Astronomy | How old is the universe? New measurements are 13.77 billion years old

A pair of recently published papers shows that the universe is 13.772 billion (plus or minus 39 million) years old.

This is good! It also agrees with some earlier measurements of the universe created in a similar way. Also cold.

What is it No The quiet is that it does not appear to reduce the increasing discrepancy in measurements taken in different ways, which attain a few hundred million years of age. While this may not seem like a big deal, it is actually a very big problem. Both groups of methods must achieve the same age, and they do not. This means that there are some basic things we are missing about the Universe.

New observations were made using a six-meter dish at the Atacama Cosmology Telescope (or ACT) in Chile that is sensitive to light in the microwave portion of the spectrum between infrared light and radio waves. When the universe was very small it was very hot and dense, but after about 380,000 years after the Big Bang it cooled so that it could become transparent. It was as hot as the Sun’s surface at that time, and the light it emitted was more or less in the visible part of the spectrum, the kind of light we see with our eyes.

But the universe has since expanded, a lot. That light has lost a lot of energy, and has turned red again, fighting us to that extent; Literally the wavelength has become longer. It is now in the microwave portion of the spectrum. It is also everywhere, literally in every part of the sky, so we call it cosmic microwave background or CMB.

A large amount of information is stored in that light, so by scanning the sky with a ‘SEC-like scope, we can measure conditions in the universe when it was just 380,000 years old.

The ACT covered 15,000 square degrees of more than a third of the entire sky! Looking at about 5,000 square degrees of that survey, they were able to determine much of the behavior of the young universe, including its age. Combined with the results of the Wilkinson Microwave Anisotropy Probe (or WMAP), he attained 13.77 billion years of age. This also agrees with the value of the European Planck mission, which also measured microwaves from the early universe.

They can also measure the expansion rate of the universe. The expansion was first discovered in the 1920s, and what astronomers have found is that an object far away from us was rapidly moving away from us. Some people were seen moving away from us twice as fast. This rate of expansion is known as the Hubble constant, and is measured in speed per distance: how fast an object moves versus how far.

The new observations yield a value for this continuation of 67.6 1.1 1.1 km / s / megapark (a megaparsec, abbreviated as Mpc, is a distance unit convenient in some aspects of astronomy, with 3.26 million light-years. Is equal to, and slightly ahead of, the distance) for the Andromeda Galaxy, if that helps). Therefore, due to cosmic expansion, an object must be 1 Mpc away from us at 67.6 km / s, and a 2 Mpc twice that at 135.2 km / s, and so on. It’s a bit more complicated than this, but that’s it.

And this is a problem. There are many ways to measure the Hubble continuum – looking at supernovae in distant galaxies, observing gravitational lenses, observing giant clouds of gas in distant galaxies, and so on – and many of them a large number, about 73 or so Km / s / Mpc. Those numbers are Close, Which is reassuring in some ways, but very different that it is extremely shocking. They must agree, and they do not.

They also attain different ages for the universe. A high Hubble constant means that the universe is expanding rapidly, so it does not require that much time to get to its current size, making it smaller. A less constant means that the universe is older. So while the expansion rate may seem esoteric, it is directly linked to the more fundamental concept of how old the universe is, and the two groups of methods get different numbers.

So which one is correct? This is a difficult question to answer, and probably the wrong one to ask. One is better Why don’t they agree?

There is an obvious point, and that both of these methods are correct, but They are measuring two different parts of the universe.. CMB watchers are examining the universe when it was less than a million years old. Other people are looking at the universe when it was already something One billion Years old. Perhaps the rate of expansion changed during that time.

In other words, perhaps Hubble is not stable. A constant, I mean.

The methods themselves may have problems, but they have been tested in many ways and in so many different ways in each group that it seems to be very rare at this point.

The flaw is clearly in the universe, and not in itself. Or, better said (sorry, Bard, and maybe John), the flaw lies in the way we measure the universe. It is doing what it does. We just have to find out why.

Many papers have been published about this, and it is no exaggeration to say that this is one of the biggest and worst problems of cosmology.

A personal view. My first job after doing my PhD was working in a part of Cosb, the cosmic background explorer, who saw CMB and confirmed that the Big Bang was real. The measurements were good at the time, but there was room for improvement. Then WMPA came along, and Planck, and now ACT, and these measurements have been made with incredible accuracy. Astronomers call it high-precision cosmology, a kind of inside joke, because for a long time, we barely knew these numbers.

Astronomers are so good at the moment that a discrepancy of 10% is considered a major problem, when a factor of two on day one was considered to be fine. It has been a real pleasure to see improvement in this area over time, because The better we get it, the better we understand the universe as a whole.

Yes, we are having some problems. But these are huge problems.

Nevertheless, hopefully we will resolve them soon. Because when we do, it means that our understanding has taken another big leap.


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