Mysterious Space Object Found at Cosmic Dawn

One-of-a-Kind Gas Blob Discovered in Early Universe

Apr 22, 2009

A giant blob of gas named Himiko lies at the edge of the visible universe and keeps its true nature a secret.

Astronomers have discovered a strange, huge collection of gas that lies as far back in time and in the universe as scientists can see. Objects such as this one are known as extended Lyman-Alpha blobs and are believed to be precursors to galaxies. However, this particular blob, named Himiko, existed when the universe was just 800 million years old, or 12.9 billion light-years away. The rest of the known Lyman-Alpha blobs existed when the universe was quite a bit older, at 2 to 3 billion years old. Himiko is 55,000 light-years across, an order of magnitude larger than what is expected for an object at this distance in the young universe.

Astronomers Surprised by Himiko Discovery

Masami Ouchi of the Observatories of the Carnegie Institution was the leader of the international team that made the discovery. "The farther out we look into space, the farther we go back in time," he explains. "I am very surprised by this discovery. I have never imagined that such a large object could exist at this early stage of the universe's history. According to the concordance model of Big Bang cosmology, small objects form first and then merge to produce larger systems. This blob had a size of typical present-day galaxies when the age of the universe was about 800 million years old, only 6 percent of the age of today's universe!"

The scientists were even hesitant to point their telescopes at the blob in the first place, believing it was a foreground interloper. "But we tried anyway," says Ouchi. "Then, the spectra exhibited a characteristic hydrogen signature clearly indicating a remarkably large distance – 12.9 billion light years!"

What Is Himiko?

The object's faintness does not allow the researchers to understand its physical origins, so for now, astronomers just don't know its true nature. They know that it is one of the most distant objects ever found and that it is a giant blob of gas, but the rest is speculation. Some possibilities are:

Himiko is seen in a time period known as the cosmic dawn. The cosmic dawn epoch lasted from about 200 million to 1 billion years after the Big Bang. It is also known as the reionization epoch. It is the farthest back in time that scientists can currently see; a transition period when neutral hydrogen began to form quasars, stars, and the first galaxies.

With improved instrumentation in the future or the possibility of discovering similar objects to Himiko, astronomers may one day be able to nail down just what this elusive object is.

The copyright of the article Mysterious Space Object Found at Cosmic Dawn in Deep Space Astronomy is owned by Kelly Whitt. Permission to republish Mysterious Space Object Found at Cosmic Dawn in print or online must be granted by the author in writing.