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Universe’s 1st Objects After Big Bang Possibly Seen by NASA Telescope

New observations from a NASA space telescope have spotted what may be the very first objects created in the universe in unprecedented detail, scientists say.

The faint objects, imaged in infrared light by NASA’s Spitzer space telescope, might be hugely massive stars or black holes, but are too distant to see individually.

The Big Bang is thought to have kick-started the universe about 13.7 billion years ago. At first, the universe was too hot and dense for particles to be stable, but then the first quarks formed, which then grouped together to make protons and neutrons, and eventually the first atoms were created. After about 500 million years, the first stars, galaxies and black holes began to take shape.

The scientists can’t confirm for sure that the objects they see date from the early universe, but say that’s the most likely explanation.

“These objects would have been tremendously bright,” Alexander “Sasha” Kashlinsky of NASA’s Goddard Space Flight Center in Greenbelt, Md., said in a statement Thursday (June 7). “We can’t yet directly rule out mysterious sources for this light that could be coming from our nearby universe, but it is now becoming increasingly likely that we are catching a glimpse of an ancient epoch.”

Spitzer spotted these ancient structures after observing two patches of sky for more than 400 hours each. The telescope sees in infrared light, the long-wavelength range of the electromagnetic spectrum that’s less energetic than optical light. [Infrared Pictures from the Spitzer Space Telescope]

The researchers first removed all known stars and galaxies from the images. What was left over showed lumps of structure in a pattern consistent with how very distant objects are thought to cluster together.

The light spied by Spitzer has probably traveled for billions of years to reach us. It would have started out as optical or ultraviolet light, but over time stretched until it became infrared.

While Spitzer, which launched in 2003 and orbits the sun in an unusual Earth-trailing path, has made inroads in observing these objects, scientists are waiting for the James Webb Space Telescope to make major progress in understanding them.

James Webb, billed as the successor to the Hubble telescope, is an $8.8 billion infrared observatory due to launch in 2018.

“This is one of the reasons we are building the James Webb Space Telescope,” said Glenn Wahlgren, Spitzer program scientist at NASA Headquarters in Washington, D.C. “Spitzer is giving us tantalizing clues, but James Webb will tell us what really lies at the era where stars first ignited.” 

The researchers report their findings in a paper in The Astrophysical Journal.

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A New View of the Tarantula Nebula (via Chandra)

Huge “Structure” of Satellites Found Orbiting Milky Way — Grouping of galaxies puts cosmology “basically in a shambles,” scientist says.

A huge “structure” of satellite galaxies and star clusters has been found wheeling around the Milky Way, according to a new study.

The discovery surprised scientists, in part because the structure might spell trouble for theories of dark matter, the mysterious, invisible substance that’s thought to make up about 23 percent of the mass in the universe.

The finding is only the latest to question dark matter’s existence—last week, for instance, astronomers announced that they’d failed to detect dark matter in the sun’s neighborhood, even though the substance should be there, according to accepted theory.

In the new study, led by Marcel Pawlowski of the University of Bonn in Germany, astronomers reconstructed the locations of the Milky Way’s known satellites using sources ranging from 20th-century photographic plates to recent images from the Sloan Digital Sky Survey.

The team found that the Milky Way’s roughly 20 companions—including dwarf galaxies and blobs of stars known as globular clusters—are distributed in a tidy plane that orbits at a right angle to our galactic disk.

“This is completely contrary to what we expect from theory,” said study co-authorPavel Kroupa, also of the University of Bonn.

“You should be able to look in any direction and still find some satellite galaxies.” That’s because current models of galaxy formation—which are based on dark matter’s existence—predict that the Milky Way’s companions originally came from many different directions and so should have settled into a more or less spherical distribution.

“The logical implication of this [discovery] is that there is no dark matter,” Kroupa said.

Cosmology in “Shambles”?

According to the standard theory of galaxy formation, dark matter was the gravitational scaffold upon which normal matter coalesced to form galaxies in the early universe.

As larger galaxies such as the Milky Way formed, the theory goes, leftover material amassed into hundreds of smaller satellites spread evenly around their host galaxies.

To explain the odd arrangement of satellites around the Milky Way, the Bonn team proposes that our home galaxy collided with a galactic neighbor about 11 billion years ago, which corresponds with the age of the oldest known satellite dwarf galaxy.

According to this idea, the Milky Way stripped material from the other galaxy, and gravity gathered the debris to form dwarf galaxies and globular clusters, which have remained in a plane around the Milky Way ever since, study leader Pawlowski said.

The team asserts that this model deals a significant blow to dark matter, since it shows that galaxies can form without the theoretical substance.

“It means that we have to completely and utterly rethink cosmology,” Kroupa said. “Cosmology is basically in a shambles now.”

Dark Matter Still Viable

But other astronomers aren’t quite ready to give up on dark matter.

“Although the alignment they find is intriguing, it is very premature to conclude that dark matter is in trouble,” said Ken Rines, of Western Washington University in Bellingham.

“Galaxy formation is a very tricky business. We certainly don’t understand the details, and these details may … explain the alignment that they find,” Rines said.

“Although dark matter may eventually be proven wrong, the alignment of dwarf galaxies is more likely a puzzle than a fatal flaw.”

Sukanya Chakrabarti, an astrophysicist at Florida Atlantic University, is also skeptical that the new study rewrites galaxy formation.

The study team’s galaxy-collision scenario can explain the positions of the satellite dwarf galaxies, she concedes.

But that model doesn’t explain why the satellites act as if they have more mass than can be explained by their visible matter alone—one of the main reasons scientists think dark matter exists.

Any alternative to dark matter “must not only reproduce where the stuff is but what its mass is as well,” Chakrabarti said.

(Related: “Dark Matter Hits the Average Human Once a Minute?”)

Study author Kroupa counters that “this is not a problem, because it has already been demonstrated many times with other data that other theories of gravity—such as MOND—describe galaxies excellently, including the satellite galaxies.”

Short for Modified Newtonian dynamics, MOND is a tweaked version of Newton’s theory of gravity, which proponents say can explain the observed motions of stars and galaxies without resorting to dark matter.

Still, Chakrabarti said, it’s also not surprising that current dark matter simulations can’t explain the Milky Way satellites’ unusual orientation.

While the simulations do a good job of modeling the evolution of large-scale structure in the universe, they’re less reliable when it comes to modeling the scale of individual galaxies, which involves interactions between many more variables, she said.

“If you neglect these things and you’re trying to do a very detailed analysis—like where all the satellite galaxies are distributed—you’re going to come up with some discrepancies,”  Chakrabarti said.

“The current simulations of galaxy formation are incomplete,” she continued, “but that doesn’t imply that dark matter isn’t a viable notion.”

Ker Than, National Geographic News