Astronomers discovered a River of hydrogen flowing through space on 28 January 2014. Scientists had discovered the never seen before river using the Green Bank Telescope (GBT) of National Science Foundation’s Robert C. Byrd.
The River flow in nearby galaxy named NGC 6946 and is around 22 million light years from Earth. Team of scientists was led by D.J. Pisano from West Virginia University.
It may help the scientists to explain how certain spiral galaxies keep up their steady pace of star formation.
Until now, scientists have discovered that the fuel for star formation had to come from somewhere. Spiral galaxies like Milky Way typically maintain a rather tranquil but steady pace of star formation.
Rivers of hydrogen-known as cold flows may be ferrying hydrogen through intergalactic space, fuelling star formation. But this was too diffused to detect, until now.
Others, like NGC 6946, which is located approximately 22 million light years from Earth on the border of the constellations Cepheus and Cygnus, are much more active, though less-so than more extreme starburst galaxies.
This raises the question of what is fuelling the sustained star formation in this and similar spiral galaxies.
Using the GBT, Pisano was able to detect the glow emitted by neutral hydrogen gas connecting NGC 6946 with its cosmic neighbors. This signal was simply below the detection threshold of other telescopes.
The GBT’s unique capabilities, including its immense single dish, unblocked aperture, and location in the National Radio Quiet Zone, enabled it to detect this tenuous radio light.
Astronomers have long theorized that larger galaxies could receive a constant influx of cold hydrogen by syphoning it off other less massive companions.
In looking at NGC 6946, the GBT detected just the sort of filamentary structure that would be present in a cold flow, although there is another probable explanation for what has been observed.
It is also possible that sometime in the past this galaxy had a close encounter and passed by its neighbors, leaving a ribbon of neutral atomic hydrogen in its wake.