Earth has traveled for the last 33,000 years through a cloud of radioactive debris left behind by ancient star explosions, deep sea sediments
- Researchers investigated deep-sea sediment to search for radioactive isotopes
- They found examples of iron-60 that is formed in the explosions of dying stars
- The isotopes must have fallen to Earth and into the oceans 33,000 years ago
- They also found earlier examples of the isotope that suggested that the Earth and the entire solar system were slowly moving through this interstellar supernova remnant.
We are all traveling through a cloud of ancient radioactive debris left behind by supernova explosions, according to a team of researchers looking into the ocean.
By conducting deep-sea research, experts from the Australian National University have unraveled the mystery surrounding the space around our solar system.
The team investigated sediment dating back 33,000 years with a sensitive mass spectrometer and found traces of the isotope iron-60 formed as stars die.
For the past thousand years, the solar system has been moving through a dense cloud of gas and dust, and the team believes that this iron-60 is sinking into our oceans.
While the isotope is radioactive and takes 15 million years to decay, it is not dangerous for humans, according to the research team, because it is a very light substance.
By researching deep sea sediments, experts from the Australian National University have unraveled the mystery surrounding the space around our solar system. Stock image
Professor Anton Wallner, who led the study, said the age of the sediment suggests that the isotopes left on Earth were produced from a supernova.
There is a cloud of dense matter that passes through the solar system – called Local Interstellar Cloud – consisting of dust, gas and plasma.
“These clouds may be remnants of previous explosions of supernovae, a powerful and super-bright explosion of a star,” said Professor Wallner.
If this cloud had originated from a supernova over the past few million years, it would contain iron-60, so the team decided to look for more recent sediment to find out.
Sure enough, there was iron-60 in the sediment at extremely low levels – equal to radioactivity levels in space far below the earth’s natural background levels.
The distribution of the iron-60 corresponded to the recent journey of the earth by the local interstellar cloud.
But the iron-60 extended further back and was spread over the entire measurement period of 33,000 years.
Iron-60 is radioactive and decays completely within 15 million years, which means that iron-60 found on Earth arrived here from nearby supernovae before settling on the ocean floor.
Professor Wallner previously found traces of iron-60 at about 2.6 million years ago, and possibly another at about 6 million years ago.
There is a cloud of dense matter that passes through the solar system – called the Local Interstellar Cloud – consists of dust, gas and plasma and the solar system passes through it
The lack of correlation with the time of the solar system in today’s local interstellar cloud seems to raise more questions than it answers, Wallner said.
First, if the cloud was not formed by a supernova, where did it come from? And second, why is there iron-60 so evenly distributed across space?
‘There are recent papers suggesting that iron-60 can trap prisoners in dust particles in the interstellar medium,’ said Professor Wallner.
‘The Iron-60 could thus have originated from even older explosions of supernovae, and what we are measuring is a kind of echo. More details are needed to resolve these details. ‘
The findings are published in the journal PNAS.
SUPERNOVAE GETS WHEN IN A GIANT STAR EXPLODES
A supernova occurs when a star explodes, throwing clutter and particles into space.
A supernova burns for only a short time, but it can tell scientists a lot about how the universe began.
One type of supernova has shown scientists that we live in an expanding universe, one that is growing at an ever-increasing rate.
Scientists have also determined that supernovae play an important role in the distribution of elements throughout the universe.
In 1987, astronomers saw a ‘titanic supernova’ in a nearby galaxy that flew at more than 100 million senses (image)
There are two known types of supernovae.
The first type occurs in binary galaxies when one of the two stars, a carbon-oxygen-white dwarf, orbits its companion star.
Eventually, the white dwarf collects too much dust, causing the star to explode, resulting in a supernova.
The second type of supernova occurs at the end of the life of one star.
When the nucleus no longer has nuclear fuel, some of its mass flows into its nucleus.
Eventually, the nucleus is so heavy that it cannot withstand its own gravity and the nucleus collapses, resulting in another gigantic explosion.
Many elements found on Earth are made in the core of stars and these elements travel through to form new stars, planets and everything else in the universe.
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