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Astronomy

The Center of the Universe: here, there and everywhere

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For quite a long time, people thought that we were at the center of the Universe. And why wouldn’t they? The Sun, the Moon, even the stars all seem to revolve around our world. There’s a famous anecdote involving the philosopher Kierkegaard and a friend talking about this on one occasion. “Why do people say that it was natural to think that the sun went round the earth rather than that the earth turned on its axis?,” Kierkegaard wondered, to which his friend replied, “I suppose, because it looked as if the Sun went around the Earth.” “And what would it look like if the Earth revolved around the Sun?” the Danish philosopher replied, no doubt rhetorically.

Polish astronomer Copernicus finally “moved” the Earth from the center of the Universe, putting the Sun in its place, however we now know we’re actually on the fringes of a rather unremarkable galaxy, one of the billions that exist in space. We’re probably not at the center, but could we eventually figure out where that is? I mean, if there was a Big Bang, that point from which everything began has to be it, right? Well, not exactly.

In the late 1920s, American astronomer Edwin Hubble figured out that the celestial “smudges” we used to call nebulae were actually other galaxies, located a lot farther away from us than we previously thought. The Universe just got a whole lot bigger! Working with the 100-inch telescope at Mt. Wilson Observatory (the largest such instrument of its day) and using techniques developed by Henrietta Leavitt (one of the great scientific minds of the early 20th century you probably never heard of), Hubble discovered that these galaxies were moving away from us – in fact the farther away they were, the faster they were moving, which suggested that the Universe was expanding (now known as Hubble’s law).

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Other scientists then took the next logical step: if you go back in time, the entire Universe must have been an unimaginably small, infinitely dense point, from which everything emerged. This became known as the Big Bang theory. But here’s the thing – the Big Bang wasn’t an explosion in space, it was the expansion of space itself, which means it “happened” everywhere all at once.

There’s an analogy often used to explain this, and it involves a balloon. Take a balloon and draw a few dots on its surface, each representing a galaxy. Now inflate it. You’ll notice that as the balloon expands, all the dots move away from each other (gravity, by the way, keeps the galaxies themselves from expanding). Also, you couldn’t really say any one of those dots is in the center – in a sense, that’s exactly how the geometry of the cosmos works out.

So in a way, there is no center of the Universe. But if you’re a glass half full kind of person, you could also argue that yourself, like any other observer, is in the center. The people of Wallace, Idaho, seem to be that kind of people. On September 25, 2004, the mayor of Wallace proclaimed his city to be the center of the Universe, more precisely a sewer cover in one of the town’s intersections. Scientifically, it’s as valid (or invalid) a location as any.

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

The exciting Lunar Standstill will be streamed live from Stonehenge

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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.

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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.

 

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Astronomy

It’s true that the Earth is not orbiting the sun right now

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Some of the diagrams and animations that show how the planets move around the sun are not quite accurate. To be more precise, they are making the planets’ orbits easier to understand so that teachers don’t have to explain barycenters to kids who are still getting used to the idea that Earth isn’t the only planet in the universe.

Most of the time, the way you learn about how planets move around the sun looks like the video below.

But this version is easier to understand. The Sun has about 1,048 times the mass of Jupiter, making it the largest object in the Solar System. However, gravity works both ways. For the same reason that the Earth pulls on itself, you pull on the Earth as well, though it is much smaller.

“Kepler’s third law describes the relationship between the masses of two objects mutually revolving around each other and the determination of orbital parameters,” NASA says.

“Think about a small star that circles a bigger star. The two stars actually move around the same mass center, which is called the barycenter. That’s always the case, no matter how big or heavy the things are. Using a massive planet to measure how fast a star moves around its barycenter is one way that planetary systems linked to faraway stars have been found.

To keep things simple, we say that the planets go around the Sun. But because the Sun has the most mass, the barycenter of the Solar System’s objects is usually close to it. However, because of Jupiter and Saturn’s orbits and effects, it is almost never inside the Sun. The paths look a bit more like the video below, which was made by planetary astronomer and science communicator James O’Donoghue.

Because of this, the Earth is not orbiting a point inside the Sun right now because the barycenter is not there. We are not going around the sun, but that point in space.

“Planets orbit the Sun in general terms,” O’Donoghue says on Twitter, “but technically, they don’t orbit the Sun alone because the gravitational influence of (mainly) Jupiter means planets must orbit a new point in space.”

“The planets do orbit the Sun, of course; we are just being pedantic about the situation,” he said. “The natural thinking is that we orbit the Sun’s center, but that very rarely happens, i.e., it’s very rare for the solar system’s center of mass to align with the Sun’s center.”

Things that are smaller, like planets and their moons, are the same way. The Earth and Moon go around a point about 3,100 miles (5,100 kilometers) from the Earth’s center. This path changes as the moon moves farther away from the earth.

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Astronomy

NASA’s flyby of Europa shows that “something” is moving under the ice

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Europa’s surface has marks that show the icy crust is vulnerable to the water below. The most important thing is that Juno’s recent visit shows what might be plume activity. If this is real, it would let future missions take samples of the ocean inside the planet without having to land.

Even though it’s been almost two years since Juno got the closest to Europa, its data is still being looked at. Even though Juno has been going around Jupiter since 2016, the five pictures it took on September 29, 2022, were the closest views of Europa since Galileo’s last visit in 2000.

Some might say that’s a shocking lack of interest in one of the Solar System’s most interesting worlds, but it could also have been a good way to see how things had changed over time.

Europa is the smoothest object in the solar system because its ocean keeps it from sinking to the surface. Still, it’s not featureless; Juno saw some deep depressions with steep walls that are 20 to 50 kilometers (12 to 31 miles) wide, as well as fracture patterns that are thought to show “true polar wander.

In a statement, Dr. Candy Hansen of the Planetary Science Institute said, “True polar wander occurs if Europa’s icy shell is separated from its rocky interior. This puts a lot of stress on the shell, which causes it to break in predictable ways.”

The shell that sits on top of Europa’s ocean is thought to be rotating faster than the rest of the moon. This is what true polar wandering means. People think that the water below is moving and pulling the shell along with it. Ocean currents are thought to be causing this. The currents are most likely a result of heat inside Europa’s rocky core, which is heated up as a result of Jupiter and its larger moons pulling on Europa and turning it into a large stress ball.

The ocean and ice could stretch and compress parts of the ice, which is how the cracks and ridges that have been seen since Voyager 2 visited were made.

A group under the direction of Hansen is viewing images of Europa’s southern half. The scientist said, “This is the first time that these fracture patterns have been mapped in the southern hemisphere. This suggests that true polar wander has a bigger effect on Europa’s surface geology than was thought before.”

Ocean currents are not to blame for all of Europa’s map changes. It appears that optical tricks can even fool NASA. Hansen said, “Crater Gwern is no longer there.” “JunoCam data showed that Gwern, which was once thought to be a 13-mile-wide impact crater and one of Europa’s few known impact craters, was actually a group of ridges that crossed each other to make an oval shadow.”

But Juno gives more than it takes away. The team is interested in what they’re calling the Platypus because of its shape, not because it has a lot of parts that shouldn’t go together. Ridges on its edge look like they are collapsing into it. The scientists think this might be because pockets of salt water have partially broken through the icy shell.

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The Europa Clipper would find these pockets to be fascinating indirect targets for study, but the dark stains that cryovolcanic activity might have left behind are even more intriguing.

“These features suggest the possibility of current surface activity and the existence of liquid water beneath the surface on Europa,” stated Heidi Becker from the Jet Propulsion Laboratory. There is evidence of such activity in the geysers of Enceladus, but there is still uncertainty regarding whether it is currently happening on Europa.

Engaging in such an endeavor would enable the sampling of the interior ocean to detect signs of life simply by flying through a plume and gathering ice flakes without the need for landing or drilling.

It seems that in the past, there was a significant shift of over 70 degrees in the locations of features on Europa’s surface, although the reasons for this remain unknown. However, at present, polar wander only leads to minor adjustments.

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