THEORY THAT CHALLENGES EINSTEIN'S PHYSICS COULD SOON BE PUT TO TEST

Scientists behind a theory that the speed of light is variable - and not constant as Einstein suggested - have made a prediction that could be tested.

Imperial College London
by Hayley Dunning 25 November 2016

Einstein observed that the speed of light remains the same in any situation, and this meant that space and time could be different in different situations.

The assumption that the speed of light is constant, and always has been, underpins many theories in physics, such as Einstein’s theory of general relativity. In particular, it plays a role in models of what happened in the very early universe, seconds after the Big Bang.

The idea that the speed of light could be variable was radical when first proposed, but with a numerical prediction, it becomes something physicists can actually test. If true, it would mean that the laws of nature were not always the same as they are today.

– Professor João Magueijo

But some researchers have suggested that the speed of light could have been much higher in this early universe. Now, one of this theory’s originators, Professor João Magueijo from Imperial College London, working with Dr Niayesh Afshordi at the Perimeter Institute in Canada, has made a prediction that could be used to test the theory’s validity.
Structures in the universe, for example galaxies, all formed from fluctuations in the early universe – tiny differences in density from one region to another. A record of these early fluctuations is imprinted on the cosmic microwave background – a map of the oldest light in the universe – in the form of a ‘spectral index’.

Working with their theory that the fluctuations were influenced by a varying speed of light in the early universe, Professor Magueijo and Dr Afshordi have now used a model to put an exact figure on the spectral index. The predicted figure and the model it is based on are published in the journal Physical Review D.

Cosmologists are currently getting ever more precise readings of this figure, so that prediction could soon be tested – either confirming or ruling out the team’s model of the early universe. Their figure is a very precise 0.96478. This is close to the current estimate of readings of the cosmic microwave background, which puts it around 0.968, with some margin of error.

Radical idea

Professor Magueijo said: “The theory, which we first proposed in the late-1990s, has now reached a maturity point – it has produced a testable prediction. If observations in the near future do find this number to be accurate, it could lead to a modification of Einstein’s theory of gravity.
“The idea that the speed of light could be variable was radical when first proposed, but with a numerical prediction, it becomes something physicists can actually test. If true, it would mean that the laws of nature were not always the same as they are today.”

The testability of the varying speed of light theory sets it apart from the more mainstream rival theory: inflation. Inflation says that the early universe went through an extremely rapid expansion phase, much faster than the current rate of expansion of the universe.

the Horizon problem

These theories are necessary to overcome what physicists call the ‘horizon problem’. The universe as we see it today appears to be everywhere broadly the same, for example it has a relatively homogenous density.

This could only be true if all regions of the universe were able to influence each other. However, if the speed of light has always been the same, then not enough time has passed for light to have travelled to the edge of the universe, and ‘even out’ the energy.

As an analogy, to heat up a room evenly, the warm air from radiators at either end has to travel across the room and mix fully. The problem for the universe is that the ‘room’ – the observed size of the universe – appears to be too large for this to have happened in the time since it was formed.

The varying speed of light theory suggests that the speed of light was much higher in the early universe, allowing the distant edges to be connected as the universe expanded. The speed of light would have then dropped in a predictable way as the density of the universe changed. This variability led the team to the prediction published today.

The alternative theory is inflation, which attempts to solve this problem by saying that the very early universe evened out while incredibly small, and then suddenly expanded, with the uniformity already imprinted on it. While this means the speed of light and the other laws of physics as we know them are preserved, it requires the invention of an ‘inflaton field’ – a set of conditions that only existed at the time.

‘Critical geometry of a thermal big bang’ by Niayesh Afshordi and João Magueijo is published in Physical Review D.

THE MOST IMPORTANT SYMPOSIUM ON ASTROBIOLOGY

We think this is the most important event ever happened considering the possibility of extraterrestrial life.

It is organized by NASA, it is open to the public, and will be broadcasted through web-cam on the Internet.

Therefore, we recommend to turn on your computers, laptops, notebooks, tablets or intelligent cellular phones, and click on this URL: https//cohen/ac.arc.nasa.gov/loc

This symposium  marks a clear difference with the meeting convened on last July by the French GEIPAN, which until today has been kept in secret. No public was allowed, no webcam or videos were broadcasted, and we came to know that the people who participated in that meeting called CAIPAN has been asked to keep silence until GEIPAN officially reports about the papers presented in that meeting.

We are ending September and still waiting for GEIPAN to publish the proceedings of CAIPAN.

In the meantime, we welcome this NASA symposium.  To see the program go to:

https://astrobiology.nasa.gov/media/medialibrary/2014/05/Symposium_Societal_Impact_of_Astrobiology_9-18-2014.pdf

HUBBLE DETECTED WATER IN FIVE EXOPLANETS

These are great news for astronomers and particularly astrophysicists.

Using the Space Telescope Hubble, to teams of scientists from NASA and the University of Maryland were capable to detect the presence of water in five exoplanets.

Those are WASP-17b, HD209458b, WASP-12b, WASP-19b and XO-1b. The signals receive are not all equal. The stronger signals indicating the presence of water has been detected on.

 "We're very confident that we see a water signature for multiple planets," said Avi Mandell, a planetary scientist at NASA's Goddard Space Flight Center in Greenbelt, Md., and lead author of an Astrophysical Journal paper, published this week describing the findings for WASP-12b, WASP-17b and WASP-19b.

"This work really opens the door for comparing how much water is present in atmospheres on different kinds of exoplanets, for example hotter versus cooler ones."

The studies were part of a census of exoplanet atmospheres led by L. Drake Deming of the University of Maryland in College Park. Both teams used Hubble's Wide Field Camera 3 to explore the details of absorption of light through the planets' atmospheres.

Based on an article published by SPACE TODAY

EXOPLANET EARTH-LIKE IN MASS AND SIZE

by Jennifer Chu for MIT News
Boston MA (SPX) Nov 01, 2013

In August, MIT researchers identified an exoplanet with an extremely brief orbital period: The team found that Kepler 78b, a small, intensely hot planet 400 light-years from Earth, circles its star in just 8.5 hours - lightning-quick, compared with our own planet's leisurely 365-day orbit.

 

From starlight data gathered by the Kepler Space Telescope, the scientists also determined that the exoplanet is about 1.2 times Earth's size - making Kepler 78b one of the smallest exoplanets ever measured.

Now this same team has found that Kepler 78b shares another characteristic with Earth: its mass. By analyzing the movement of its host star, Kepler 78, the scientists determined that the exoplanet is about 1.7 times as massive as the Earth. From the same measurements, they calculated that the planet's density is 5.3 grams per cubic centimeter, closely resembling Earth's density (5.5 grams per cubic centimeter).

While its similarities to Earth likely end with Kepler 78b's size and mass, Winn says there is still more to learn about the planet, such as its surface and atmospheric composition - a goal that the group plans to pursue next.
(Source: SPACE DAILY)

SEARCH FOR ALIEN LIFE MORE COMPLICATED THAT THOUGHT, SCIENTISTS SAY

(UPI) October 8, 2013 - Finding life on distant exoplanets may be more difficult than scientists thought, researchers from China, the United Sates and Argentina said Monday.

Recent observations of several planet-hosting M dwarf stars –the focus of current efforts to find Earth-like planets—showed ultraviolet properties of the small stars are quite different from those of the sun, which could further complicate the search for alien life, the researchers told a meeting of the American Astronomical Society Division form Planetary Sciences in Denver.

That could complicate the search for chemical signs of life, they said.

Feng Tian, a professor at Tsinghua University,  and his U.S. and Argentine colleagues have shown that the atmospheres of a hypothetical habitable planet around such a star could build up significant levels of oxygen –one possible “signature” for alien life –even in the absence of any such life.

“Before we can claim the discovery of life on exoplanets, we have to examine the stars harboring these planets more carefully”! the researchers said.

Other scientists agreed.

“The authors of this paper make an important point regarding the confidence we could have in the detection of O2 simultaneously with H2O and CO2, as a biosignature in the spectrum of an Earth-like exoplanet around an M star”, Alain Leger of the Institute d’Astrophysique Spatiale at University of Paris said.