Connect with us

Astronomy

Collision with Mercury-like object billions of years ago might have created Earth’s magnetic field

blank

Published

on

The Sun and 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.

Giant impact hypothesis

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.

Who doesn’t enjoy listening to a good story. Personally I love reading about the people who inspire me and what it took for them to achieve their success. As I am a bit of a self confessed tech geek I think there is no better way to discover these stories than by reading every day some articles or the newspaper . My bookcases are filled with good tech biographies, they remind me that anyone can be a success. So even if you come from an underprivileged part of society or you aren’t the smartest person in the room we all have a chance to reach the top. The same message shines in my beliefs. All it takes to succeed is a good idea, a little risk and a lot of hard work and any geek can become a success. VENI VIDI VICI .

Astronomy

You can watch and listen to gravitational waves coming from everywhere in the universe

blank

Published

on

blank

Gravitational waves can be turned into sound very easily. The little chirp changes into little sounds as soon as the blocks hit each other. One of those chirps is my ringtone when my phone has sound, which doesn’t happen very often. The people at Audio Universe have now made the gravitational wave data even better.

In a 3D video, the sounds of gravitational waves hit you from the direction in the sky where it is thought they came from. The sound effects and visualization are both great. There are tiny vibrations in space-time that can hit you as you move your mouse, phone, or VR headset.

Like other sonification projects, it gives blind and visually impaired people a way to get involved in astronomy. It works well with other methods like the Tactile Universe. But that’s not the only reason why they do it.

“We want to do this for three reasons.” It helps researchers look into big, complicated datasets with lots of dimensions. It could be used to make educational materials that are immersive and interesting. Rose Shepherd from Newcastle University says, “It can also make astronomy easier for more people to understand, which is an important thing.” “Making things easier to get makes them better for everyone.”

Being able to listen to the emission lines of celestial objects is one of the most interesting things about sonification for research. As an object moves, its light spectrum peaks spread out, and sonification can make something that is barely noticeable to the eye seem very clear to the ear.

This is helpful in more than one field, though. The group has thought about how adding sound to different datasets could make them better. Warming Stripes is a cool example of this. This is a simple image that shows changes in temperature over time by using a series of stripes, from blue to red. The stripes on the right side get redder as we move from the left to the right. The left side shows decades ago. It is great to see how the climate crisis is getting worse, and now sound adds a little more to it.

“By adding sounds, it can give your data an emotional meaning.” Shepherd explained, “You can use that to show the data how you feel.” “We didn’t mean for the Warming Stripes sonification to make people feel stressed, but it was interesting to see how they reacted instead of just watching the video.”

Audio Universe is making a sonic toolkit that many people can use to make their own resources.

She gave a talk about the audio universe at the National Astronomy Meeting at the University of Hull this week.

Continue Reading

Astronomy

There Is A Hotly Debatable Twin To The Search For Extraterrestrial Intelligence

blank

Published

on

blank

Humanity has been trying to find signals from extraterrestrial civilizations for more than a century. Prior to focusing our eyes and ears on the galaxy and universe beyond, early efforts in the Search for Extraterrestrial Intelligence (SETI) concentrated on listening for messages from within the Solar System.

There have been no alien signals found thus far in these searches. While one signal remains enigmatic, it most likely stems from a human or natural source. But given that we (aside from our stray signals) don’t broadcast ourselves on a regular basis, is it unreasonable to assume that alien civilizations would do the same?

Messaging for Extraterrestrial Intelligence, or METI, is introduced. While it wouldn’t be accurate to state that humanity hasn’t communicated with the cosmos, there have undoubtedly been a few. The Golden Records are audio and visual files that NASA’s Voyager I and Voyager II spacecraft “selected to portray the diversity of life and culture on Earth.” Aliens will probably never find these. However, we have also sent other signals, like the Arecibo Message, which was directed about 21,000 light-years from Earth toward the globular star cluster M13. With only 210 bytes of data, the message was small but contained information about the 4 billion people that lived on Earth at the time, a stick figure of a person, a double helix, and a drawing of the Arecibo radio telescope that sent the message.

The organization METI International was founded in 2015 with the intention of communicating with extraterrestrial civilizations. They delivered a similar message to the super-Earth exoplanet GJ273b in October 2017, which is only 19 light-years away from Earth and may be habitable.

This is where METI becomes a little contentious. A map of the solar system was also included in the Arecibo message, and there are (very speculative) reasons why we might not want to communicate with aliens in our cosmic backyard or even send a return address.

The explanation of the Fermi paradox offered by what is now widely referred to as the “Dark Forest Hypothesis” is one of the reasons METI is controversial.

In short, it looks like the universe is full of planets that might be habitable, but we have never picked up a signal from an alien civilization.

The very dark Dark Forest Hypothesis, which is explained in Liu Cixin’s Remembrance of Earth’s Past trilogy, says that alien civilizations hide their existence because you can’t be sure what other civilizations want. There’s no way for you to know if they are hostile or friendly, or what their intentions are.

It’s possible that you, as a friendly civilization, find an alien civilization that is also friendly and about the same level of development as yours. You know you’re nice, but you don’t know if they’re also calm. Even worse, because of how far away these civilizations are and how long it takes to receive light and signals from them, you have no idea how their society has changed since the signal from them reached yours. In the meantime, they may have made huge technological leaps. This means that even if the planet you are looking at seems peaceful and not too far ahead of yours, everything could have changed by the time the light gets to you.

On top of that, there is the pressure of resources. According to the books, you also know from your own planet that life uses and spreads all the resources it can find. But there are only so many resources in the universe.

You still have to deal with the fact that you don’t know if they know that you are peaceful if you decide that they are peaceful. Since they think or even just suspect that you are bad, it makes sense that they would try to kill you before you could kill them. You could talk to them, just like you can here on Earth, to reassure them even more of your plans. In space, though, it could take hundreds or even thousands of years for your new message to get there. During that time, they could have began an attack to destroy you. With this many red flags, Liu comes to the conclusion that the only smart thing for a civilization that wants to stay alive is to hide in the forest and kill any civilizations that make noise, before they kill you.

Scientists are serious about the idea of hostile aliens, even though the idea became popular in fiction. In 2015, Stephen Hawking started a project to look for alien civilizations. He talked about why it might not be a good idea to say hello back.

According to Space.com, Hawking told the crowd, “We don’t know much about aliens, but we know a lot about humans.” “If you look at history, interactions between humans and less intelligent creatures have often been terrible for them, and interactions between civilizations with advanced and primitive technologies have also been bad for the less advanced.” If someone reads one of our messages, they might be billions of years ahead of us. They will be much stronger if that’s the case, and they might not value us more than we value bacteria.

However, the Dark Forest theory is still a long way from being proven. It is important to think about hostile aliens when deciding whether to contact other species and who should make that decision. David Brin, an American author and scientist, asked “whether small groups of zealots should bypass all institutions, peer critique, risk appraisal, or public opinion, to shout ‘yoohoo’ into a potentially dangerous cosmos.”

In a way, the fact that METI exists could be used to show that the Dark Forest Hypothesis is wrong. Let’s say there are very advanced societies out there. Assuming that some people in these advanced civilizations have access to advanced broadcast technology is a reasonable thing to do. Another reasonable guess is that if they were that advanced, they would have built this civilization with science instead of magic.

The civilizations would probably gather information about other star systems in the same way that we do, unless they have a good reason for not wanting to know about life beyond their own planet. Assuming that this information and broadcast technology aren’t somehow limited across all civilizations, there must be some people who would be crazy enough to try to get in touch with other civilizations. While obviously speculating wildly, it’s possible that an alien METI species that likes to take risks might try to warn other, younger civilizations about how the universe is like a dark forest. Also, we haven’t heard from these actors, which could mean that the long silence has a different cause than the Dark Forest Hypothesis.

That, or the METI problem, might only happen in new civilizations that send out messages every so often before we learn about the universe’s dark side and do everything we can to stay quiet.

Continue Reading

Astronomy

The exciting Lunar Standstill will be streamed live from Stonehenge

blank

Published

on

blank

People are very interested in Stonehenge, which is one of those famous landmarks. It is very clear that it lines up with the sun at the solstices, but no one is sure what the monument is for. But over the next few months, scientists will look at a different kind of alignment: some stones may be lined up with the lunar standstill.

In the sky, things move around. The sun moves around during the year because the planet is tilted with respect to its orbit. This means that the times when it rises and sets are often different. Stonehenge is set up so that the first rays of dawn on the summer solstice and the last rays of sunset on the winter solstice both pass through the middle.

But outside the stone circle are the so-called station stones, whose purpose is unknown. They don’t seem to be linked to the sun, but to the moon. The position of the moonrise and moonset changes because the moon’s orbit is tilted relative to the earth. This is similar to how the sun moves. But it doesn’t happen every year. The cycle goes around and around for 18.6 years.

When the Moon is at the fullest point of its cycle, it moves from 28.725 degrees north to 28.725 degrees south in just one month. The next one won’t happen until January 2025. This time is called the major lunar standstill (lunistice). So, scientists will be going to Stonehenge several times over the next few months, even during the major standstill, to figure out how the monument might line up with our natural satellite.

Talked to Heather Sebire, senior property curator at Stonehenge. “I think the moon in general would have been very important to them.” “And you know, maybe they could do things they couldn’t do other times when there was a full moon because there was more light.”

“They think the lunar standstill might have something to do with this because there are four rocks out in the middle of the ocean that are called “station stones.” Only two of them have been found so far. Together, they form a rectangle, which some people think may have something to do with the setting outside the circle.

When the Moon is in a minor standstill, its distance from the Earth is between 18.134° north and south. It will happen again in 2034.

As archaeologists continue to look into this interesting alignment, Stonehenge wants everyone to join in the fun. As usual, people will be able to enter the circle for the solstice, which this year is the earliest since 1796. However, the next day will be all about the lunistice.

blank

 

 

 

 

 

 

 

 

 

 

 

 

As the moon rises, the lunar standstill event can only be seen online. You can watch the livestream from the comfort of your own home and wonder with the researchers if this great monument was also lined up with the Moon.

 

Continue Reading

Trending