Astronomy
Collision with Mercury-like object billions of years ago might have created Earth’s magnetic field
Even though we’ve ventured far into the Solar System and our telescopes tell us a lot about distant stars and galaxies, the inner workings of our own planet have remained shrouded in mystery. Much of our understanding of what it’s like underground comes from what are basically educated guesses, because we can’t really send probes down to the center of the Earth. There are some inconsistencies with these models, like why are there certain elements in certain proportions in the planet’s crust and below. Another great problem is the fact that we don’t understand how the Earth’s magnetic field, one of our planet’s most remarkable features, works. Recently, however, scientists from Oxford University have proposed a possible explanation – and it involves a massive collision between our planet in its youth and a smaller cosmic object with similar properties to those of Mercury.
Like all the objects in our Solar System, the Earth formed from a huge molecular cloud which spanned this area of space about 4.6 billion years ago. The early Solar System comprised a young Sun and probably hundreds of planets, which either merged with one another or were destroyed by the gas giants like Jupiter. A lot of what we know about the composition of these celestial objects comes from the study of meteors called chondrites, which have underwent little change since the formation of the Solar System billions of years ago. It is believed these kinds of rocks clumped together under the effect of gravity to create the rocky planets, such as our own.
There is, however, recent data which isn’t entirely consistent with this model, namely there’s a shortage of neodymium relative to samarium (two elements with magnetic properties) in the Earth’s crust and mantle compared to what is found in chondrites. This seems like a rather small and innocuous anomaly, nevertheless it’s something which puzzles scientists, who haven’t managed to come up with a definitive explanation for it. The key, according to Oxford University geochemists Bernard J. Wood and Anke Wohlers, who have recently published a study in the journal Nature, might be sulfur, which made its way into our planet’s crust after it “consumed” a Mercury-like planet the size of Mars early in its lifetime.
The closest planet to the Sun, Mercury is a hellish world which is, quite appropriately, rich in sulfur. If an object with a similar composition had smashed into the Earth billions of years ago, the resulting iron sulfide would have mixed with the neodymium, and subsequently sink together to the core of the planet, leaving relatively more samarium (which is more attracted to the silicate rock found in the crust and mantle and thus less likely to sink) behind in the upper layers. To test this hypothesis, scientists added sulfur to a mixture of elements similar in composition to the primitive Earth, then subjected the sample to the conditions thought to have occurred at that time: temperatures between 1,400 and 1,640 °C (2,550 and 3,000 °F) and pressures of 1.5 gigapascals (150,000 times greater than atmospheric pressure at sea level today!). After adding sufficient quantities of sulfur, neodymium sunk to the core of the model planet, which is consistent with the theory.
This could also help explain the origin of the Earth’s magnetic field. The planet’s inner core is mainly made up of iron which is extremely hot (about 5,700 °C or 10,300 °F), however due to the huge pressure at that depth it remains solid. Higher up, where the pressure isn’t as high, there’s an outer core of molten iron. Convection currents, as well as the Coriolis force cause the flow of torrents of liquid iron, generating electric currents, which then produce magnetic fields. How the core has remained molten for so long is another mystery, which could be explained by uranium (which generates heat through nuclear decay) also sinking together with the iron sulfide.
If a catastrophic collision with a Mercury-like, Mars-sized object sounds a bit far-fetched, it shouldn’t. Remember there were perhaps hundreds of objects of various sizes and compositions in the young Solar System, which were constantly jostling for position. It’s not inconceivable that many of them collided, getting obliterated and forming new celestial bodies or merging together. In fact, one of the most widely accepted theories regarding the Moon’s formation holds that the Earth collided with a planet similar in size to Mars we now call Theia, and the debris resulting from the crash clumped together to form our sole natural satellite.
Artist’s depiction of the impact between the Earth and a planet-sized object called Theia, which could have resulted in the formation of the Moon. Scientists believe a similar impact could have created our planet’s magnetic field. Image: NASA/JPL-Caltech.
Our magnetic field is extremely important for life on Earth. It protects us from potentially devastating solar winds and cosmic rays, which would otherwise blow away the upper parts of the atmosphere, and it also helps birds, turtles, and even humans navigate. You could argue we wouldn’t be here if it didn’t exist. Although the collision with a Mercury-like object hypothesis is still far from being confirmed, it’s still interesting to think life on Earth was made possible by a cataclysmic event early in our planet’s lifetime.
If there are extraterrestrial civilizations within a reasonable distance capable of detecting our unintentional transmissions, there exists a possibility, albeit small, that among the initial signals they intercept, they could receive the commencement of the 1936 Olympic Games. Therefore, in the unlikely event that they do receive these signals, we might come across a speech by Adolf Hitler during our first encounter with an alien species.
“Naturally, this was not the initial transmission,” clarified Seth Shostak, a senior astronomer at SETI, during an interview with RealClearScience. “However, it was emitted at a sufficiently high frequency to penetrate the ionosphere.”
In the movie Contact, this ultimately became the initial communication that mankind received from an extraterrestrial society. The entities promptly returned the signal to Earth, unaware of the profound consequences that transmitting broadcasts of Adolf Hitler from outer space would have on the targeted species they were endeavoring to establish communication with. It is similar to greeting a random person and then unintentionally reciting a chapter from Mein Kampf.
Fortunately, it is highly likely that we won’t encounter this issue because extraterrestrial civilizations shouldn’t be able to distinguish the signal strengths.
“The power consumption would have been minimal, and the antenna used would not have had a specific direction,” Shostak elaborated. “The notion that extraterrestrial beings might intercept it is highly improbable.”
However, it is possible that we may receive significantly more alarming initial communications, as individuals have been deliberating on X (Twitter) and Reddit.
What would be the scariest message humanity could receive from outer space? pic.twitter.com/HKEzb7JBnI
— Curiosity (@MAstronomers) April 21, 2024
It appears that people are primarily focused on receiving warnings from extraterrestrial civilizations right now, possibly as a result of a recent unnamed television series.
What would be the scariest message humanity could receive from outer space?
byu/silly_vasily inAskReddit
"Be quite they will hear you!"
— Adam Taylor (@ATaylorFPGA) April 21, 2024
According to certain proposed resolutions to the Fermi Paradox, which ask why we haven’t detected any signs of advanced extraterrestrial civilizations, the explanation is that these civilizations are intentionally concealing their presence due to the apprehension of their own annihilation.
Another concern is the possibility of receiving an unclear message that extraterrestrial beings will provide us with limited information, apart from the fact that they are en route.
What would be the scariest message humanity could receive from outer space? pic.twitter.com/HKEzb7JBnI
— Curiosity (@MAstronomers) April 21, 2024
What would be the scariest message humanity could receive from outer space?
byu/silly_vasily inAskReddit
One theory, called the Zoo Hypothesis, is related to this topic. The theory posits that extraterrestrial beings possess knowledge of our existence but deliberately confine us within a designated “zoo” to allow for our evolutionary and societal development. This parallels humanity’s practice of preserving certain areas as nature reserves and refraining from engaging with uncontacted tribes. Based on this hypothesis, it is possible that we may receive contact once we have reached a satisfactory level of technological and societal development and potentially be accepted into a community of other galaxies.
Although there is a prevailing apprehension that initiating communication with an extraterrestrial civilization will probably elicit fear due to humanity’s historical tendency to fear the unfamiliar, there is a potentially more alarming notion.
Orbex, a small launch company based in the UK, got more money from backers, including Scotland’s national bank. The company is now getting ready for its first orbital launch, but the date for that mission has not yet been set.
With its start in 2015, Orbex is one of only a few companies in Europe racing to make the next generation of launch vehicles. The retirement of the Ariane 5 and big delays to the Ariane 6 and Vega C rockets have left a huge gap that these companies are trying to fill. Without these vehicles, there is almost no native launch capacity coming out of Europe.
But Orbex also has a chance because of his absence. The company is working on what is sometimes called a “microlauncher.” It is a two-stage vehicle called Prime that is only 19 meters tall and can take up to 180 kilograms of payload. Rocket Lab’s Electron is the most similar. It’s only a meter shorter, but it can take up to 300 kilograms.
The fact that Orbex is small is not a problem for the company. In fact, Orbex CEO Philip Chambers told TechCrunch via email that the company is seeing “positive market conditions” for its product.
“There is a pent-up demand for sovereign launch capabilities,” he said. “We are seeing an exponential growth of satellites being launched into LEO, and demand for launch is far exceeding supply. At the moment, it’s not possible to launch a single kilogram from Europe.” “We will let European customers choose how to launch their own payloads and let them launch European payloads from European soil.”
Prime will take off from a new spaceport being built with money from the UK’s national space agency in Sutherland, which is in northern Scotland. The end goal is to use a patented recovery technique that the company calls REFLIGHT. This is an interstage device that sits between the rocket stages. When the booster comes off, four “petals” will unfold and, along with a parachute, create enough drag for a soft landing in the ocean.
It’s possible that a bigger car will be made in the future, but Chambers made it clear that Prime was the company’s top goal. He did say, though, that many of the rocket’s main technologies could be used with bigger packages.
Considering the laws of physics, it would be logical for Orbex to explore the option of using larger vehicles in order to compete on cost per kg.
The company is starting its Series D round with £16.7 million ($20.7 million) in new funding, including investments from Octopus Ventures, BGF, Heartcore, EIFO, and other contributors. Following the closure of a £40.4 million ($50 million) Series C in October 2022, Orbex has secured additional capital. Although a spokesperson has confirmed that the new funding will assist Orbex in accelerating the development of Prime, ensuring its readiness and scalability for the launch period, the specific launch window has not been announced yet.
Astronomy
The Ingenuity team at NASA has received their last communication, however, the Mars helicopter is still operational
The NASA Ingenuity team said goodbye to the helicopter robot and got one last message before splitting up. But ingenuity isn’t really dead yet; it will still be collecting data on Mars.
It’s a great little robot, and in April 2021, it was the first to fly powered and controlled on a planet other than Earth. That’s not easy to do because conditions on Mars are so different.
“The Red Planet has a much lower gravity—one-third that of Earth’s—and an extremely thin atmosphere with only 1% of Earth’s pressure at the surface,” NASA said in a press release after Ingenuity’s first flight. “This means there are relatively few air molecules with which Ingenuity’s two 4-foot-wide (1.2-meter-wide) rotor blades can interact to achieve flight.”
It was planned for the helicopter, which was really just a prototype, to make five flights over 30 days on Mars. Instead, it made 72 flights over 1,000 days. NASA started to use it to get a bird’s-eye view of Mars and find interesting places for Perseverance to go back and look at more closely.
On the 72nd flight, unfortunately, Ingenuity had to make an emergency landing and lost touch with Perseverance. When they got in touch again, pictures from the helicopter showed that a rotor was badly damaged, so Ingenuity would not be able to fly again.
Even though the helicopter can’t fly anymore, it can still gather information and send it to Perseverance. Perseverance then sends the information to Earth through NASA’s Deep Space Network. Before the Ingenuity team broke up, they got one last message from Ingenuity and ate cake to celebrate.
“I’m sorry, Dylan Thomas, but Ingenuity will not be going gently into that good Martian night,” said Josh Anderson, lead of the Ingenuity team at JPL. “It’s hard to believe that she still has something to give after more than 1,000 days on Mars’ surface, 72 flights, and one rough landing.” Because of how hard this amazing team worked, not only did Ingenuity do better than we thought it would, but it may also teach us new things in the years to come.
After stopping in “Valinor Hills” to rest, the robot’s job will be to gather data while it’s still, hopefully learning useful things about the planet’s environment before future missions with people.
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