You want to know something funny? We don’t actually know how our planet formed. We have a broad general idea, but the finer details are a lot trickier to unravel.
We do have a model that is currently accepted as the most likely explanation so far: that Earth formed from the gradual accretion of asteroids. However, even here, there are some facts about the formation of our planet that are challenging to explain.
A new paper, combining experimentation with modeling, has revealed a new formation pathway that much more neatly fits the characteristics of Earth.
“The prevailing theory in astrophysics and cosmochemistry is that the Earth formed from chondritic asteroids. These are relatively small, simple blocks of rock and metal that formed early on in the Solar System,” said planetologist Paolo Sossi of ETH Zurich in Switzerland.
“The problem with this theory is that no mixture of these chondrites can explain the exact composition of the Earth, which is much poorer in light, volatile elements such as hydrogen and helium than we would have expected.”
There’s a whole bunch of question marks over the planet formation process, but scientists have been able to piece together a general picture. When a star forms from a dense clump of matter in a molecular cloud of dust and gas in space, the material around it arranges into a disk that orbits and spools into the growing star.
That disk of dust and gas doesn’t just contribute to the waistline of a growing star – small densities within that swirl also aggregate into smaller, cooler clumps. Small particles collide and stick together, first electrostatically, then gravitationally, forming larger and larger objects that can eventually grow into a planet. This is called the accretion model, and it’s strongly supported by observational evidence.
But if the rocks that stick together are chondrites, that leaves a big open question about the missing lighter, volatile elements.
Scientists have posed various explanations, including heat generated during the collisions that could have vaporized some of the lighter elements.
That, however, doesn’t necessarily track either: heat would have vaporized lighter isotopes of elements, with fewer neutrons, according to recent experimental work led by Sossi. But lighter isotopes are still present on Earth in roughly similar ratios to those found in chondrites.
So Sossi and his colleagues set out to investigate another possibility: that the rocks that combined to make Earth were not chondritic asteroids from Earth’s general orbital neighborhood, but planetesimals. These are larger bodies, the “seeds” of planets that have grown to a size large enough to have a differentiated core.
“Dynamic models with which we simulate the formation of planets show that the planets in our Solar System formed progressively. Small grains grew over time into kilometer-sized planetesimals by accumulating more and more material through their gravitational pull,” Sossi said.
“What is more, planetesimals that formed in different areas around the young Sun or at different times can have very different chemical compositions.”
They ran N-body simulations, altering variables such as the number of planetesimals, along the “Grand Tack” scenario, in which a baby Jupiter moves first closer to the Sun, and then back again to its current position.
Under this scenario, the motion of Jupiter in the early Solar System had an extremely perturbing effect on the smaller rocks swirling around, scattering planetesimals into the inner disk.
The simulations were designed to produce the inner Solar System we see today: Mercury, Venus, Earth and Mars. The team found that a diverse mixture of planetesimals with different chemical compositions could reproduce Earth as we see it today. In fact, Earth was the most likely outcome of the simulations.
This could have important implications not just for the Solar System, and understanding the varying compositions of the rocky planets therein, but other planetary systems elsewhere in the galaxy.
“Even though we had suspected it, we still found this result very remarkable. We now not only have a mechanism that better explains the formation of the Earth, but we also have a reference to explain the formation of the other rocky planets,” Sossi said.
“Our study shows how important it is to consider both the dynamics and the chemistry when trying to understand planetary formation. I hope that our findings will lead to closer collaboration between researchers in these two fields.”
The team’s research was published in Nature Astronomy.
“Alien bases” may be hiding off the coast of Alaska, researchers say
An organization of civilian volunteers dedicated to the study of
unidentified flying objects (UFOs) has issued a statement based on
decades of studying eyewitness reports. According to Mutual UFO Network,
“alien bases” may be hiding off the coast of Alaska, reports the-sun.com.
say the deep waters in this region may hold something surprising. After
analyzing reports from the ship’s crew from 1945, they hypothesized
that alien objects could be lurking underwater, off the coast of the
Alleged sightings of alien spacecraft nearly 80 years ago
have become a key point in research. Members of the organization believe
that UFOs move over water and may have “bases.”
allege crew members on a U.S. Army transporter ship sailing past Island
Adak saw a massive UFO sized 150 to 200 feet emerge from the water.
Although these reports are nowhere to be found, UFO enthusiasts believe
the unidentified flying vehicles likely were used to commute to
different supposed alien bases hiding in the deep waters.
the “secret reports” of the sailors aren’t available, investigators
have taken it upon themselves to unravel the mystery surrounding the
unidentified flying objects and they believe the ocean has alien bases
that humans aren’t aware of.
Enthusiasts claim that UFOs may be
using “underwater networks” or wormholes as superhighways to travel
between points in the universe. UFO researcher Johnny Enoch added that
such objects could serve as a vehicle for aliens.
There are also
theories that other places on Earth could serve as bases for alien life.
A mountain in Seoul, South Korea is believed to be hiding a UFO,
according to Dr. Steven Greer.
An episode of the series “The
Alaska Triangle” features satellite imagery that claims to show one of
the “alien bases” in the Pacific Ocean off the coast of California.
another researcher featured in the program showed markings from the sea
bed that she claimed could have been roadways for aliens.
the mysteries of the ocean remain unsolved, researchers continue their
search, trying to unravel the mystery of what may be hiding in the
depths of the waters off the coast of Alaska.
Enormous City-Size Comet Racing Towards Earth Grows ‘Devil Horns’ After Massive Eruption
A volcanic comet the size of a mid-sized US city has
violently exploded for the second time in four months as it continues
racing toward the earth. And following the massive eruption, the cloud
of ice and gas sprouted what looked like a pair of gigantic devil horns.
The city-sized comet, named 12P/Pons-Brooks, is a cryovolcanic — or
cold volcano — comet. It has a solid nucleus, with an estimated diameter
of 18.6 miles, and is filled with a mix of ice, dust and gas known as
cryomagma. The nucleus is surrounded by a fuzzy cloud of gas called a
coma, which leaks out of the comet’s interior.
When solar radiation heats the comet’s insides, the pressure builds up
and the comet violently explodes, ejaculating its ice-cold innards into
space through seeping cracks in the nucleus’s shell.
Live Science report:
On Oct. 5, astronomers detected a large outburst from 12P, after the
comet became dozens of times brighter due to the extra light reflecting
from its expanded coma, according to the British Astronomical Association (BAA), which has been closely monitoring the comet
Over the next few days, the comet’s coma expanded further and developed its “peculiar horns,” Spaceweather.com
reported. Some experts joked that the irregular shape of the coma also
makes the comet look like a science fiction spaceship, such as the
Millennium Falcon from Star Wars.
The unusual shape of the comet’s coma is likely due to an irregularity in the shape of 12P’s nucleus, Richard Miles, a BAA astronomer, told Live Science after the comet’s previous eruption.
The outflowing gas is likely being partially obstructed by a notch
sticking out on the nucleus, Miles said. As the gas continues to expand
away from the comet, the irregularity in the coma’s shape becomes more
defined and noticeable, he added.
12P is currently hurtling toward the inner solar system, where it
will be slingshotted around the sun on its highly elliptical 71-year
orbit around our home star — similar to the green comet Nishimura, which
pulled off a near-identical maneuver on Sept. 17.
12P will reach its closest point to Earth on April 21, 2024, when it
may become visible to the naked eye before being catapulted back toward
the outer solar system. It will not return until 2095.
This is the second time 12P has sprouted its horns this year. On July
20, astronomers witnessed the comet blow its top for the first time in
69 years (mainly due to its outbursts being less frequent and harder to
spot during the rest of its orbit). On that occasion, 12P’s coma grew to
around 143,000 miles (230,000 km), which is around 7,000 times wider
than the comet’s nucleus.
It is unclear how large the coma grew during the most recent
eruption, but there are signs the outburst was “twice as intense” as the
previous one, the BAA noted. By now, the coma has likely shrunk back to
near its normal size.
As 12P continues to race toward the sun, there is a high probability
that we will witness several more major eruptions. It is possible that
those eruptions will be even bigger than the most recent one as the
comet soaks up more solar radiation, according to Spaceweather.com.
But 12P is not the only volcanic comet that astronomers are currently
monitoring: 29P/Schwassmann-Wachmann (29P) — the most volatile volcanic
comet in the solar system — has also had several noticeable eruptions
in the last year.
In December 2022, 29P experienced its largest eruption in around 12 years, which sprayed around 1 million tons of cryomagma into space. And in April this year, for the first time ever, scientists accurately predicted one of 29P’s eruptions before it actually happened, thanks to a slight increase in the comet’s brightness in the lead-up to the icy explosion.
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