The Birth of a Universe

A&S researchers and students explore the origins of our universe through space telescopes.

Massimiliano Galeazzi loves the look on the faces of his undergraduate research assistants when they come to his astrophysics lab and he hands them a screwdriver and a wrench.

“Some students think that astrophysics is all about writing equations on a piece of paper,” says Galeazzi, associate professor of physics in the College of Arts & Sciences (A&S) and the lead scientist in a 2012 NASA rocket launch. “Our job is building rocket experiments. We don’t have engineers or technicians, so my students and I do everything ourselves.”

Galeazzi and his colleague Kevin Huffenberger, another assistant professor of physics, are two excellent examples of A&S researchers working on the frontlines of world-changing discovery. Their field is astrophysics and their shared research focus is cosmology — nothing less than the composition and origins of the universe.

For the wrench-wielding undergraduates in Galeazzi’s lab, or the freshmen in Huffenberger’s Descriptive Astronomy course, A&S offers a rare opportunity to grab a front-row seat in the unraveling of a cosmic mystery.

Both Galeazzi and Huffenberger work with space telescopes. Since the earth’s atmosphere blocks certain light waves from reaching conventional observatories, astrophysicist launch telescopes into space to get the clearest pictures of far-off stars, galaxies, black holes and nebulae.

But even the most sophisticated space telescopes must contend with background signals and optical anomalies that can distort the data. It’s Galeazzi and Huffenberger’s job to analyze those background signals and distortions so that the global scientific community obtains the most accurate images of local phenomena and the deepest expanses of space.

“If you look at the sky with your naked eye, you see total darkness punctuated by points of light — stars and galaxies,” says Galeazzi, who concentrates on the X-ray portion of the spectrum. “If you look at the sky using an X-ray telescope, you don’t see darkness at all, but a pervasive diffuse glow.”

The problem is that the source of the diffuse glow is local, meaning within a few hundred light years of Earth. So if you want to examine distant objects using an X-ray telescope — for example, black holes are only visible using X-ray detection, as are the remnants of exploded stars called supernovae — you have to see past the local haze.

Galeazzi’s task is to figure out exactly where these local diffuse X-ray emissions are coming from and understand the properties of those objects. The top candidates are a pocket of hot gas in the Milky Way called the Local Hot Bubble (LHB) and something called the Solar Wind Charge Exchange (SWCX) caused by ionized solar wind particles colliding with atoms of hydrogen and helium outside the Earth’s atmosphere.

“In some ways,” says Galeazzi, “it’s easier to point a telescope at a separate galaxy than to observe phenomena from within. Because we’re inside the LHB and the SWCX, it’s harder to study them.”

In December 2012, Galeazzi and a team of scientists from NASA and other U.S. institutions, in collaboration with U.S. Navy and the U.S. Army, launched a sounding rocket carrying instruments built in Galeazzi’s A&S lab. The 56-foot, two-stage rocket was only in space for five minutes, but it was long enough to collect X-ray data that will help Galeazzi make critical distinctions between emissions from the LHB and the SWCX.

Kevin Huffenberger, Galeazzi’s colleague at A&S, is playing a similar role with the Planck space telescope, an instrument that has been orbiting Earth since 2009 collecting data about the cosmic microwave background radiation, the oldest light in the universe.

“This radiation that we’re measuring is the afterglow of the Big Bang,” says Huffenberger, “providing a picture of the universe when it was only 380,000 years old.”

Planck made headlines in early 2013 when its freshly updated “map” of the newborn universe was released to scientists and the public. The blue and red spots on the image represent hot and cold regions in the lumpy soup of the early universe. Huffenberger notes that “hot” and “cold” are relative terms when you’re talking about a radiation source with an average temperature of 2.7 Kelvin (-455 °F). The difference between a red and blue spot on Planck’s map comes down to a few hundred millionths of a degree.

The distribution of these hot and cold spots tells us something about the composition of the universe more than 13 billion years ago and the original distribution of matter.

“There’s regular matter, dark matter, dark energy, radiation, neutrinos and more,” Huffenberger explains, “and our standard cosmological model says that the distribution of the hot and cold spots should be relatively uniform on a small scale. “But the Planck telescope,” which views the universe on the largest scale imaginable, “returned data saying that the temperature variations are more intense in one part of the sky than another.”

This anomaly has intrigued the global scientific community and challenged our understanding of how the universe has evolved. As a Planck Scientist, Huffenberger is one of only 200 researchers worldwide to review and sign scientific papers released by the Planck Mission, a collaboration between the European Space Agency and NASA.

“I’m a member of a sub-group focused on understanding how the optics of the telescope affect the signal that we measure off the sky,” Huffenberger says. Specifically, Huffenberger tries to measure the “blurriness” in Planck’s images — how much the telescope’s optics soften the images as the instrument gathers radiation from tens of billions of light years away.

Watch a video of Kevin Huffenberger discussing the cosmic microwave background radiation and Massimiliano Galeazzi discussing his NASA rocket launch.

August 15, 2013