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The First 100,000 Years of the Universe

By David Reneke

Astronomers view the first 100,000 years of the universe, and NASA outlines the scientific goals for a future landed spacecraft mission to Europa.

A new analysis of cosmic microwave background (CMB) radiation data by researchers with the Lawrence Berkeley National Laboratory has taken the furthest look back through time yet – 100,000–300,000 years after the Big Bang – and provided tantalising new hints of what might have happened.

“We found that the standard picture of an early universe, in which radiation domination was followed by matter domination, holds to a testable level using the new data, but there are hints that radiation didn’t give way to matter exactly as expected,” says Eric Linder of the Supernova Cosmology Project. “There appears to be an excess dash of radiation that is not due to CMB photons.”

Our knowledge of the Big Bang and the early formation of the universe stems almost entirely from measurements of the CMB, primordial photons set free when the universe cooled enough for particles of radiation and matter to separate. These measurements reveal the CMB’s influence on the growth and development of the large-scale structure we see in the universe today.

Linder’s team analysed satellite data from the European Space Agency’s Planck mission and NASA’s Wilkinson Microwave Anisotropy Probe, which pushed CMB measurements to higher resolution, lower noise and more sky coverage than ever before. “While our analysis shows the CMB photon relic afterglow of the Big Bang being followed mainly by dark matter as expected, there was also a deviation from the standard that hints at relativistic particles beyond CMB light,” Linder says.

Linder says the prime suspects behind these relativistic particles are “wild” versions of neutrinos, the phantom-like subatomic particles that are the second most populous residents (after photons) of today’s universe. The term “wild” is being used to distinguish primordial neutrinos from their modern counterparts.

Another suspect is dark energy, the anti-gravitational force that accelerates our universe’s expansion. Again, however, this would be from the dark energy we observe today. Early dark energy could have been the driver that seven billion years later caused the present cosmic acceleration.

Its actual discovery would not only provide new insight into the origin of cosmic acceleration, but perhaps also provide new evidence for the highly controversial string theory and other concepts in high energy physics.

Europa Landing to Look for Signs of Life

NASA’s Science Definition Team has identified three main priorities for a future landed spacecraft mission to Europa that will study the potential habitability of the ice-covered moon of Jupiter. The scientific goals are to: investigate the composition and chemistry of Europa’s ocean; characterise the thickness, uniformity, and dynamics of its icy shell; and study its surface geology.

“Landing on Europa and touching its surface is a visionary goal of planetary science,” says Dr Robert Pappalardo of NASA’s Jet Propulsion Laboratory. “This is a difficult technical challenge that is probably many years away. Understanding the key scientific questions to be addressed by a future Europa lander helps researchers focus on the technologies required to get us there, and analyse the necessary data that might be attained by a precursor mission that could scout out landing sites.”

The majority of exobiologists believe Europa is the most likely place in our solar system beyond Earth to have life today, and a landed mission would be the best way to search for it. “Landing on the surface of Europa is a key step in the astrobiological investigation of that world,” says Dr Christopher McKay of NASA’s Ames Research Centre.

The scientists hope that surface materials, possibly near the linear crack features, will include biomarkers carried up from the ocean.

Just imagine: strange creatures could be swimming in Europa’s icy alien waters kept alive and thriving from warm thermal vents generated from the moon’s hot interior. Even if past life was carried in these waters their remains could now be frozen in the ice. A lander could detect them.

Most of what scientists know of Europa has been gleaned from a dozen or so close flybys from NASA’s Voyager 2 spacecraft in 1979. Our closest view of Europa was provided by the Galileo spacecraft, which orbited the Jupiter system from 1995 to 2003.

Even in these fleeting, paparazzi-like encounters, scientists have seen enough to convince them that the moons of the giant planets hold the best chance of finding life beyond Earth.

David Reneke is an astronomy lecturer and teacher, a feature writer for major Australian newspapers and magazines, and a science correspondent for ABC and commercial radio. Subscribe to David’s free Astro-Space newsletter at www.davidreneke.com