There Are Vast Clouds of Tiny, Shimmering Diamonds Hiding All Over Our Galaxy
An image of the cosmic microwave background in the Milky Way, which scientists now know is distorted by glowing nanodiamonds.
Credit: ESA

Huge clouds of tiny, glowing diamonds are floating through empty regions of the Milky Way, and astronomers had no idea the little shimmering particles were there. The discovery could help researchers figure out what happened in the first moments after the Big Bang.

That's because these diamonds have turned out to be the culprit behind a mysterious phenomenon scientists have termed "anomalous microwave emissions" (AMEs). The galaxy is full of strange, gentle microwave beams, but until recently, scientists had no idea where they came from.

The most common theory was a group of organic molecules called polycyclic aromatic hydrocarbons (PAHs). But in a new paper published today (June 11) in the journal Nature Astronomy, a team of scientists from England, the United States and Germany proved the PAH theory wrong. The AMEs, they showed, come from spinning nanodiamonds. [Top 10 Unexplained Phenomena]

Part of the reason AMEs were such a mystery is that, for a long time, researchers hadn't been able to track them down to any precise points of origin in space, the researchers explained in a statement. AMEs were just these faint, sourceless puffs of microwave energy that appeared out of the darkness. Scientists suspected that PAHs, which are spread throughout interstellar space and do emit faint infrared radiation, might be the cause. But without a specific point of origin to study, they couldn't be sure.

Recent research also cast doubt on the PAH hypothesis. Most notably, a 2016 paper in The Astrophysical Journal showed that AMEs don't pulse and fluctuate in the same way as the infrared beams from PAHs do, suggesting they might not be linked after all.

Using the Green Bank Telescope in West Virginia and the Australia Telescope Compact Array, the new study's researchers found three clouds of dirt and dust around newborn stars (the sorts of clouds that eventually coalesce into planets and asteroids) that were emitting AMEs. But those clouds didn't contain the faint infrared signature of PAHs. However, they did contain the signatures of spinning nanodiamonds.

The researchers created computer models of the diamonds and found that hot, spinning nanodiamonds, each just 0.75 to 1.1 nanometers across (less than half the width of a strand of DNA, or about 0.00000004 inches), could produce the AMEs they recorded.

Narrowing down the source of the AMEs is a big deal, they said, because microwaves in outer space hold so much information about the ancient universe. The fingerprints of the Big Bang are still visible in outer space in what's known as the cosmic microwave background (CMB). But more recent sources of microwaves, like AMEs, mess up that picture.

The more scientists know about where microwaves in space come from, the more precise a picture they can build of the CMB. And a more precise picture of the CMB can tell scientists a lot about the first moments of the universe.

Originally published on Live Science.