Scientists are baffled after discovering a mysterious radioactive ‘blip’ deep below the Pacific Ocean
Scientists have been left baffled after discovering something vast and radioactive lurking in the depths of the Pacific Ocean.
While it might sound like the start of the next Godzilla movie, researchers say this ‘blip’ is a very real phenomenon.
An international team of scientists has found unexpectedly high levels of the rare radioactive isotope beryllium-10 in samples from the Pacific seabed.
And they believe it could have been caused by a blast of radiation from space more than 10 million years ago.
Beryllium-10 is an isotope – a variant of an element with a different number of neutrons in its atomic nuclei, formed when cosmic rays hit oxygen and nitrogen in the upper atmosphere.
After forming, this isotope falls to the ground in the rain and settles to the bottom of the seabed at a fairly constant rate.
However, when the researchers looked at samples of the seabed from 10 million years ago, they found that the levels of beryllium-10 were almost twice what they had expected.
Study author Dr Dominik Koll, from Helmholtz-Zentrum Dresden-Rossendorf, Germany, says: ‘We had stumbled upon a previously undiscovered anomaly.’
Scientists have been baffled to find something vast and radioactive lurking beneath the Pacific Ocean. Although it sounds like the plot of the next Godzilla movie, the researchers say this anomaly is very real
Researchers discovered an unexpectedly high amount of the rare radioactive isotope beryllium-10 from samples taken from the bottom of the Pacific Ocean. This compound is formed when cosmic rays hit oxygen and nitrogen in the atmosphere and falls to the ground in rain before sinking to the seabed
In their study, published in Nature Communications, the researchers looked at the accumulation of Beryllium-10 in the seabed deep below the Pacific Ocean.
These unique samples were collected from several miles beneath the water and are made up of a mixture of iron and manganese called a ferromanganese crust.
Using a highly sensitive method called Accelerator Mass Spectrometry, the researchers were surprised to find an unexpected spike in beryllium-10 levels occurring about 10 million years ago.
To ensure this wasn’t a fluke, Dr Koll and his colleagues looked at samples taken from elsewhere in the Pacific, but these samples all showed the same anomalous blip.
The researchers argue that there are two possible ways to explain this strange phenomenon: one earthly, and one extraterrestrial.
In one scenario, the unusual radioactive buildup could have been caused by the ocean circulation around the Antarctic suddenly and drastically changing 10 to 12 million years ago.
Dr Koll says: ‘This could have caused beryllium-10 to be unevenly distributed across the Earth for a period of time due to the altered ocean currents.’
‘As a result, beryllium-10 could have become particularly concentrated in the Pacific Ocean.’
The levels of beryllium-10 should have been fairly consistant though time, but researchers found a significant spike in its abundance about 10 million years ago (illstrated)
These samples (pictured left) came from a region of the northeast Pacific (shaded yellow) that currently sits by major ocean currents (red and blue lines). The researchers suggest that massive changes to thes currents 10 million years ago could have built up more beryllium-10
In the more out-of-this-world theory, something might have happened in space which exposed the Earth to a sudden burst of radiation.
This could have been triggered by the after-effects of a near-Earth supernova, which would have bathed the planet in intense radiation.
Alternatively, the planet might have briefly lost its protective solar shield, known as the heliosphere, after passing through a dense interstellar cloud.
In either case, this would mean that beryllium-10 should be unusually common 10 million ago in oceans all around the world.
Dr Koll says: ‘Only new measurements can indicate whether the beryllium anomaly was caused by changes in ocean currents or has astrophysical reason.
‘That is why we plan to analyze more samples in the future and hope that other research groups will do the same.’
Discovering that this anomaly is present all around the world could be extremely valuable for scientists looking into the distant past.
Even though radioactive isotope dating is generally accurate, researchers still need common reference points in order to compare different sets of samples.
Alternatively, the beryllium-10 could have been formed by the radioactive blast of supernova such as the one which left behind the Crab Nebula (pictured). This intense radiation would have led to more beryllium-10 forming all over the world
For example, researchers studying more recent populations can often look for the spikes in C14 isotopes associated with nuclear weapons testing to help date organisms.
Dr Koll says: ‘For periods spanning millions of years, such cosmogenic time markers do not yet exist.
‘However, this beryllium anomaly has the potential to serve as such a marker.’
So, if this spike could be found all around the world, it would let researchers compare completely different archives by synching up to the same unexpected spike 10 million years ago.
