A Cepheid in the Milky Way, RS Puppis, is seen by the Hubble Space Telescope.
Credit: Hubble Space Telescope
The universe is also moving fast, and nobody knows why.
In the early years of the Universe, right after the Big Bang, everything blew apart from everything else. We can still see the light of this explosion by observing very distant parts of the universe where light takes billions of years to reach our telescopes. And we can measure how fast things moved in these distant places. Based on this speed, we can calculate how fast the universe should expand today.
But when astronomers have tried to directly measure how fast the universe is expanding today ̵
And yet nobody knows why. [Does the Universe Have an Edge?]
Earlier observations of this increased speed still had a 1 in 3,000 chance that astronomers were wrong, which is considered quite high for an astrophysical outcome. This new paper improves astronomers' confidence. The probability of setting an observation error is 1: 100,000. It is intended to be published in the April 25 issue of The Astrophysical Journal Letters and is available on the preprint server arXiv.
"This mismatch has grown and reached a point that really can not be dismissed as coincidence. That was not what we expected," said lead author Adam Riess, Nobel laureate and astrophysicist at Johns Hopkins University, in a statement ,
Researchers relied on the same tool that astronomer Edwin Hubble used to show that the universe was expanding again in 1929: a class of pulsating stars called Cepheids.
Cepheids, the astronomer Henrietta S. Leavitt had shown in an Annals journal of the Harvard College Observatory in 1908, whose pulse was directly proportional to their brightness. This means that astronomers can find out how bright a cepheid should be, depending on how fast it pulsates. Seeing how dark it looks from Earth, you can see how much light is lost along the way and how far away it is.
To measure the speed of expansion of the universe, astronomers test the distance to the Cepheids near and far away galaxies. However, this is usually a slow task because the Hubble can only accurately measure a distant cepheid at once. The researchers developed a method that allows the space telescope to "drift" as it images the stars, dramatically increasing more than one image of them and drastically increasing the accuracy of the entire range finding.
What they found directly contradicts the predictions made on observations made by the Planck satellite of the European Space Agency, which measured the speed of the universe 380,000 years after the Big Bang.
So what does it mean that the universe almost certainly moves too fast?
"That's not fair, two experiments contradict each other," said Riess. "We measure something fundamentally different: on the one hand, we measure how fast the universe expands from today's perspective, the other is a prediction based on the physics of the early Universe and measurements of how fast it should expand if these values are not There is a very high likelihood that we are missing something in the cosmological model that connects the two eras. "
Riess does not know what the missing thing is, but for the time being He plans to further refine his measurements.
O originally published on Live Science .