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Today, our average age universe seems strangely smooth. Too smooth, actually.
While a quick push into space-time would explain what we see, science needs more than just beautiful ideas. It needs evidence that negates contradictory arguments. We could finally know where to look.
A team of physicists from the Center d'astrophysique | Harvard & Smithsonian (CfA) and Harvard University have returned to the next page on the evolution of the Universe early in order to allow us to help these patterns of inflation. to stand out from the crowd.
"The current situation with regard to inflation is that it is such a flexible idea that it can not be falsified experimentally," says theoretical physicist Avi Loeb of the CfA.
"No matter what value people measure for an observable attribute, there are still patterns of inflation that can explain it."
We have been convinced for some time that our universe is expanding – its fabric is slowly expanding under the influence of a kind of strange, "dark" energy.
If we press rewind on the universe until it is barely 10-43 second, we come to the limit of what our knowledge of physics can support. Before this moment? Geometry is so crazy that we do not know where to start.
By calculating at the back, we also find that the Universe would have had a radius of 10-ten meters at this crucial moment. It sounds tiny, of course, but it's not enough.
The light echo of the early moments of the Universe is still visible in the form of a cosmic microwave background. Curiously, this background radiation seems surprisingly uniform today.
Thermodynamics makes this observation difficult to swallow. Such uniformity means that radiation glides from one edge to the other of the universe, balancing temperature fluctuations. Yet space has grown too fast for light to follow.
For such a balancing exercise to be achievable remotely, the radius of the newborn Universe at this critical time had to be smaller.
This unconventional cosmos would have crossed early childhood at an exponential speed, reaching the size of a grain of sand in a few tens of thousandths of a second.
The story fits perfectly with what we observe, but so would other explanations that the Universe did not explode quickly.
"In some alternative theories, the size of the Universe shrinks – some do it very slowly, some very quickly," says Harvard physicist Zhong-Zhi Xianyu.
"The attributes that people have proposed so far to measure usually have trouble distinguishing different theories as they are not directly related to the changing size of the primordial universe."
Did time exist before the Big Bang? Was there some kind of inverted universe? Everyone is welcome in his pet theory about the appearance of our universe, but only one can be a winner.
To help determine which ones remain and which ones are going, researchers have proposed using observable attributes that we can associate with the discriminative characteristics of inflation-based models.
The challenge is to know how to interpret such observations as a sequence of events. What's needed, it's a kind of standardized cosmic timestamp to spell out the relevant steps, some of which might possibly totally exclude inflation.
"If we imagine all the information we have learned up to now about what happened before the Big Bang comes in the form of rolls of film footage, the" " Standard clock tells us how to read these images, "says Xingang Chen, of the CfA.
The team suggests a mechanism by which quantum fluctuations can refer to sequences of events that are reflected in patterns of vast cosmic structures.
"These signals will be very subtle to detect," says Chen.
"Microwave cosmic background radiation is one example, and the distribution of galaxies is another, we have already started looking for these signals and there are some interesting candidates already, but we need more data. "
Other cosmologists have also suggested looking for clues to the hidden past of our Universe in the whirlwinds of light and matter in the sky.
Some allude to the possible "scars" left by the black holes of a previous universe on our cosmic microwave background. Others predict that we might find signs that the revolutionary frontier we call the Big Bang has never existed.
There are many interesting ideas that explain how our universe has evolved. All that remains is to determine which we can throw in the file "good idea, shame about the facts".
This search was accepted for publication by Letters of physical examination.
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