Earth may be 60 million years OLDER than what we thought\
Earth may be 60 million years OLDER than first thought: Gases in rocks reveal when our planet’s atmosphere was formed
- Researchers in France have revealed what they claim to be Earth’s new age
- Findings are based on analysis of ancient gas in South Africa and Australia
- Study suggests the giant impact that formed the moon happened earlier than first thought
- It had been thought Earth formed 100 million years after the solar system
- But now it is believed our planet formed just 40 million years after
Researchers have claimed Earth is 60 million years older than previously thought.
Our planet was believed to have formed approximately 100 million years after the solar system started to take shape 4.6 billion years ago, but scientists now say it was actually closer to just 40 million years.
They came to the conclusion by analysing ancient gases in quartz, which showed astronomers had underestimated the timing of the impact that formed the moon – and in turn the age of Earth.
he research was presented by geochemists from the University of Lorraine in Nancy, France to the Goldschmidt Geochemistry Conference in Sacramento, California.
HOW THE MOON FORMED
Many researchers believe the moon formed after Earth was hit by a planet the size of Mars billions of years ago.
This is called the giant impact hypothesis.
The hypothesis claims the moon is debris left over following an indirect collision between our planet and an astronomical body approximately 4.5 billion years ago.
The colliding body is sometimes called Theia, after the mythical Greek Titan who was the mother of Selene, the goddess of the Moon.
They discovered an isotopic signal that indicates previous age estimates for both the Earth and the moon need to be revised.
Calculating exact dates that far back, however, is no mean feat.
Looking back into ‘deep time’ it becomes more difficult to put a date on early Earth events.
In part, this is because there is little ‘classical geology’ dating from the time of the formation of the Earth, such as an absence of rock layers from that era.
So geochemists rely on other methods to estimate early Earth events.
One of the standard techniques is measuring the changes in the proportions of different gases (isotopes) which survive from the early Earth – but even this only gives an estimate.
‘It’s not possible to give an exact date for the formation of the Earth,’ said Dr Guillaume Avice of the University of Lorraine.
‘The oldest rocks of the solar system have been dated to 4,568 million years ago – so Earth is younger than that.
‘What this work does is show Earth is older than we thought – by around 60 million years.’
The new findings were made by studying xenon gas that had been trapped in quartz crystals (stock image shown) in South Africa and Australia. The findings showed that the giant imapct that is thought to have created the moon must have happened about 60 million years earlier, meaning Earth is also similarly older
The study resets the clock for the collision between Earth’s ancestor and a planet-sized object that led to the formation of the moon.
The scientists analysed xenon gas found in quartz from South Africa and Australia which had been dated to 3.4 and 2.7 billion years respectively.
The gas sealed in this mineral is preserved like a time capsule – allowing comparisons of the current isotopic ratios of xenon with those that existed billions of years ago.
Recalibrating dating techniques using the ancient gas allowed them to refine the estimate of when Earth began to form.
This allowed them to calculate the moon-forming impact is around 60 million years older than had been thought – give or take 20 million years.
Earth and the moon are pictured here by the Galileo spacecraft on 16 December 1992. After the planet was struck by a Mars-sized object, debris surrounded Earth and eventually became the moon, which is tidally locked to our planet, meaning the same face always points our way
‘The composition of the gases we are looking at changes according to the conditions they are found in – which of course depend on the major events in Earth’s history,’ continued Dr Avice.
‘The gas sealed in these quartz samples has been handed down to us in a sort of time capsule.
‘We are using standard methods to compute the age of Earth but having access to these ancient samples gives us new data and allows us to refine the measurement.
‘The xenon gas signals allow us to calculate when the atmosphere was being formed, which was probably at the time Earth collided with a planet-sized body leading to the formation of the moon.
‘Our results mean that both Earth and the moon are older than we had thought.’
Previously the time of formation of the Earth’s atmosphere had been estimated at around 100 million years after the solar system formation.
As the atmosphere would not have survived the moon-forming impact this revision puts the age up to 40 million years after the solar sytem formation – so around 60 million years older than previously thought.
Co-researcher Dr Bernard Marty said: ‘This might seem a small difference – but it’s important.
‘These differences set time boundaries on how the planets evolved – especially through the major collisions in deep time which shaped the solar system.’
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715 new planets in outside solar system
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NASA announces 715 newly discovered planets
The Earth’s galaxy is looking far more crowded. NASA has confirmed 715 newly discovered planets outside the solar system.
Douglas Hudgins, NASA’s exoplanet exploration program scientist, called Wednesday’s announcement a major step toward the planet-hunting Kepler telescope’s ultimate goal — “finding Earth 2.0.”
It’s also a big step in “the possibility of life elsewhere,” said Lisa Kaltenegger, a Harvard and Max Planck Institute astronomer who wasn’t part of the discovery team.
Scientists using the Kepler telescope pushed the number of planets discovered in the galaxy to about 1,700. Twenty years ago, astronomers had not found any planets circling stars other than the ones revolving around the sun.
“We almost doubled just today the number of planets known to humanity,” NASA planetary scientist Jack Lissauer said in a teleconference.
Astronomers used a new confirmation technique to come up with the largest single announcement of a batch of exoplanets what planets outside our solar system are called.
Wednesday’s announcements also were about implications for life behind those big numbers.
All the new planets are in systems like ours where multiple planets circle a star. The 715 planets came from looking at just 305 stars. They were nearly all in size closer to Earth than gigantic Jupiter.
And four of those new exoplanets orbit their stars in “habitable zones” where it is not too hot or not too cold for liquid water which is crucial for life to exist.
The four new habitable zone planets are all at least twice as big as Earth so that makes them more likely to be gas planets instead of rocky ones like Earth and less likely to harbour life.
So far Kepler has found nine exoplanets in the habitable zone, NASA said. Astronomers expect to find more when they look at all four years of data collected by the now-crippled Kepler; so far they have looked at two years.
Planets in the habitable zone are likely to be farther out from their stars because it is hot close in. And planets farther out take more time orbiting, so Kepler has to wait longer to see it again.
Another of Kepler’s latest discoveries indicates that “small planets are extremely common in our galaxy,” said MIT astronomer Sara Seagar, who wasn’t part of the discovery team. “Nature wants to make small planets.”
And, in general, smaller planets are more likely to be able to harbour life than big ones, Ms. Kaltenegger said.
Keywords: NASA, Kepler telescope, exoplanets, solar system
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