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I’m often asked two very natural and related questions.

1. Why is the speed of light, usually denoted c, so astonishingly fast?
2. Why, in Einstein’s famous equation relating energy and mass — E=mc2 — does c2, a gargantuan number, appear?

It’s true that the speed of light does seem fast — light can travel from your cell phone to your eyes in a billionth of a second, and in a full second and a half it can travel from the Earth to the Moon.

And indeed the energy stored in your body is comparable to the Earth’s most explosive volcanic eruptions and to the most violent nuclear bombs ever tested — enormously greater than the energy you use to walk across the room or even to lift a heavy suitcase.

What in the name of physics — and chemistry and biology — is responsible for these bewildering features of reality? The answer is fascinating, and originates in particle physics and the resulting structure of matter. It is surprisingly intricate, though, so I’m going to approach this step-by-step over three blog posts. Here’s the first.

Refining and Rephrasing the Questions

We should start by recognizing that the second question has two sub-questions, one qualitative, and one precise:

• 2a. Why, in Einstein’s famous relation between energy E and mass m, does a gargantuan number appear?
• 2b. Why is that gargantuan number equal to the speed of light squared, i.e. c2?

We’ll see that questions 1 and 2a are almost the same question, and have largely the same answer. But as we’ll see, they aren’t phrased well yet.

The problem is that “fast” and “gargantuan” are relative terms. I can run much faster than a slug but much slower than a cheetah. I am huge compared to a bacterium, but not compared to a star. So we ought to start by restating these questions in relative terms; that will help us think them through.

• 1. Why is the speed of light so much faster than the speeds that we humans ordinarily experience?
• 2a. Why is the energy stored in the masses of ordinary objects (via E=mc2) so much larger than the energy of the ordinary processes experienced in daily life?

The Cosmos Has a Viewpoint

To get us warmed up, I’ll start with a brief quote from my book, chapter 2.

“It’s well-known that light has a characteristic speed, which scientists call c ; this is the speed at which each individual photon travels, too. As scientists discovered centuries ago, c is about 186,000 miles per second. That’s fast, in a way. Our fastest spaceships don’t come anywhere close to that speed. Though my last car was with me for fifteen years, I drove it less than 186,000 miles. At the speed c , you could circle the Earth in a blink of an eye (literally) and travel from my head to my toe in a few billionths of a second.

“And yet c is also slow. It takes light more than one second to travel to the Moon, over eight minutes to reach the Sun, and over four years to reach the next-nearest star. If we sent off a robot spaceship at nearly c to explore the Milky Way, it could visit only a few dozen nearby stars during our lifetimes.

“You and I are small, so we think light runs like a rabbit. But the universe is vast, and from its perspective, light creeps like a turtle.”

The point of this quote is to remind us that we’re not the center of the universe. We are not annointed creatures relative to whom all cosmic facts should be measured. There’s nothing unique or special about the Earth or its size, mass or temperature — nothing materially unique about animals, about mammals more specifically, or about us. The way the cosmos works is not influenced by the objects of our ordinary lives. So our own perspectives are not privileged, and we should be aware that there are other perspectives, ones from which light’s speed is slow and/or from which the energy stored in a human is tiny.

To make our questions really meaningful, then, we ought to step back and ask not just how we view the cosmos but how the cosmos views us. From the universe’s perspective, the questions really are these:

• 1. Why are humans so astonishingly slow compared to the natural speeds of the cosmos?
• 2a. Why are the energies involved in ordinary human affairs so insanely tiny compared to the natural energies one would expect from objects of human scale?

For us to understand how the universe would answer these questions, we have to understand what “natural speed” and “natural energy” might mean from a cosmic perspective. So let’s start there.

The Natural Speed

The quantity c is not just the speed of light, and so “speed of light” is not the best name for it. For instance, it is also the speed of gravitational waves. Even more important, it is the limit on the relative speed of all physical objects. That’s why I and many others often call it “the cosmic speed limit” — because that makes it clear that rather than being a property of light, it is a property of the universe. (Caution; there are lots of conceptual traps and subtleties here, some of which I’ve written about.)

This cosmic speed limit seems to be the same everywhere across the universe (based on our observations of almost unimaginably distant and ancient objects), and so every living intelligent creature in the cosmos can measure it. No other speeds are fixed and reliable in the same way. Compare it, for instance, with the speed of sound. Sound speed varies with temperature and with the material through which it travels, and so this speed is completely different in other planets’ atmospheres and oceans. It could never be used as a cosmic measure of speed that all intelligent species could agree on.

Nor should we think of human speeds of about 1 meter per second (about one yard per second) as “normal speed”. First, if we were peregrine falcons or sloths, we’d view human speed very differently. Second, the now-standard choice of “meter” to measure length and “second” to measure time is arbitrary. A blue whale is many meters long, very big in this sense. But a sufficiently intelligent species of whale wouldn’t use “meter” as their yardstick, and would instead likely define length using a “whaler”, comparable in size to a whale. We’d be a fraction of a whaler tall, and thus seem diminutive by that measure. Similarly, a sequoia tree would probably not want to use “second” as a time-frame; “hour” would be more characteristic.

So the precise way one defines distances and times and speeds, and what makes a length or a duration or a velocity large or small, are all species-dependent, planet-dependent, and perspective-dependent unless you use facts about the cosmos that everyone can agree on. And when it comes to speed, the cosmos has a view on this matter. It says:

“c is normal speed, because that’s the maximum rate at which information can travel from one place to another. No two objects can move relative to each other faster than that. No knowledge can be sent faster than that. There’s no other speed of comparable stability or of comparable importance. So typical objects should always pass each other at a speed that is a reasonable fraction of c.

“But, uhhh… WOW… you Earth-creatures are absurdly, ridiculously slow! Look at how you crawl around your planet!”

The Appearance of c2

Setting aside the issue of whether c should be viewed as large, small or normal, why is it “natural” that the energy E stored inside an object should be related to its mass m by c2? My answer follows the logic of this post, which goes into more detail about the methods of “dimensional analysis”, one of physicists’ most important tools. You may want to read it if my explanation here seems too sketchy to you.

Einstein’s basic claim was that even a stationary object has energy stored inside it. The amount of that energy, he suggested, is reflected in its mass — specifically its “rest mass” m, which is the mass as measured by an observer who is stationary relative to the object. (For more details on rest mass and on various forms of energy, see chapters 5-8 of my book.)

Any relation between energy and mass must involve the square of a speed (or the product of two speeds.) We find this already in first-year physics. In pre-Einsteinian days, the motion energy (i.e. “kinetic energy”) of a moving object was understood to be equal to an object’s mass m times its speed v squared:

• Newtonian-era motion energy = 1/2 mv2

If you tried to replace v2 with v3 or v99 , the equation would become nonsensical. (As a physicist would say it: the units on the two sides of the equation don’t match.) It would be like claiming that the height of a tree is equal to the color of its leaves — two things of completely different character can’t generally be equal.

But back to Einstein’s claim that a stationary object has energy too. The corresponding formula can’t contain v, since a stationary object has v=0. Some other speed or speeds must appear instead.

Why should that speed be c? Well, it wouldn’t make much sense for an object’s energy/mass relation to depend on the speed of some other object. Imagine if the energy in my body were my mass times the square of the speed of some ultra-distant star. Not only would this be bizarre (and inconsistent even with Galileo’s relativity), what would the formula have meant before the star was born?

No, the relationship between energy and mass for stationary objects must be universal — cosmic — and so it can only depend on speeds that are properties of the universe itself. As far as we know, the universe has only one inherent speed: c. (In fact you can prove that Einstein’s conception of relativity would be inconsistent if there were more than one basic speed.) Therefore any relation between energy and mass must be of the form E = #mc2, where # is a fixed number that someone has to figure out. There’s no other equation that could logically make any sense.

Einstein knew this, of course, even before he wrote his relativity papers. So did all his colleagues.

The fact that the # is equal to 1 is partly a historical accident of definitions, and partly, given this accident, a matter of brilliant deduction and imagination. Click here for some details.

Regarding the question as to whether E = 1/2 mc2 or E = 2 mc2 or E = 4/3 mc2, here physicists got a little lucky historically. The definition of mass was given in Newton’s day, and energy was defined later in just such as a way that, for pre-Einsteinian physics, the motion energy of a moving object is 1/2 mv2. There are sensible reasons for that definition. It is directly related to the definition of momentum as mv, mass times velocity, with no 1/2 or 2 in front. The definition of momentum was in turn was motivated by Newton’s equation F=ma, which defines what we mean by mass. If Newton had put a 1/2 in that equation, defining mass differently, then there’d be a 1/2 in Einstein’s formula too. But with the definitions that Newton and his followers used, the correct equation that matches nature is E=mc2 , with no numerical factor. That’s a nice historical accident; any change in the definition of energy or mass would have affected the sleek appearance of Einstein’s formula.

Now, why was Einstein the one to figure out that, with these definitions, the correct number in the equation is 1, when his colleagues had been trying so hard and getting so close for a couple of decades? He asked the right question, while his colleagues did not. More about that here.

So 2b is answered: in our universe, the only possible relation between E and m for a stationary object is E=#mc2, where # may depend on how one’s culture exactly defines energy and mass, but which happens, with our historical definitions of energy and mass, to be 1.

The Natural Energy

And so, from the universe’s perspective,

“The natural energy for an object with a rest mass m is something like mc2 . When the object is stationary, that’s exactly how much energy it has, and when it’s moving, it has more. And if it’s moving at a natural speed — some moderate fraction of c — then we already know from pre-Einstein physics that its motion energy will be something like 1/2 mv2 , which will be a substantial fraction of mc2 . In short, typical objects in the universe will be seen to carry internal energy mc2 and motion energy which is not so far from mc2.

“But you Earth-creatures … you are like frightened mice, keeping all your activities down to a tiptoe and a whisper! Are you trying to avoid being noticed? Are you cowards, afraid of any drama?”

The answer to the last question is “yes, absolutely”. But more on that in the next post.

Why the Energy Question is a Speed Question

I’ve already now hinted at why the energy question 2a is the same as the speed question 1. The reason the energy stored in ordinary objects seems so large in human terms is that the speed of light seems so fast in human terms.

Again,

• Einstein claimed (and it was soon confirmed in experiments) that a stationary object has internal energy mc2, where m is called the “rest mass” of the object.
• For slow objects like us, with v much less than c, we can use Newton’s approximations to Einstein’s equations, for which an object of rest mass m moving at speed v has motion energy 1/2 mv2.

This means that the ratio of an object’s motion energy, which is easily observed in ordinary life, to its internal energy, which is hidden in ordinary life, is

• (motion energy)/(internal energy) = (1/2 mv2 ) / (mc2) = 1/2 (v/c)2

This is extremely tiny if (v/c) itself is very small. And therefore, if we understand why v is so much less than c in daily life, then we will simultaneously understand why the energies of ordinary human affairs are so small compared to the internal energies of typical objects around us.

So when I return to this topic in an upcoming blog post, we’ll explore why particle physics itself assures that the speeds of daily life must be slow.

Stay tuned for the next post in this series!

You have definitely heard of electronics. You may (if you are a tech nerd like me) have heard of spintronics and photonics. Now there is also the possibility of orbitronics. What do these cool-sounding words mean?

Electronic technology is one of those core technologies that has transformed our civilization. Prior to harnessing electricity and developing electrical engineering we essentially had steam punk – mechanical, steam-powered technology. Electronics and electricity to power them, however, opened the door to countless gadgets, from electric lights, appliances, handheld devices, and eventually computer technology and the internet. I am occasionally reminded of how absolutely essential electricity is to my daily life during power outages. I get a brief glimpse of a pre-electronic world and – well, it’s rough. And that’s just a taste, with the real drudgery prolonged life without power would require.

Increasingly electronic devices are computerized, with embedded chips, possibly leading to the “internet of things”. Data centers eat an increasing percentage of our power production, and the latest AI applications will likely dramatically increase that percentage. Power use is now a limiting factor for such technology. It’s one main argument against widespread use of cryptocurrencies, for example. To illustrate the situation, Microsoft has just cut a deal to reopen Unit 1 at the Three-Mile Island nuclear power plant (not the one that melted down, that was Unit 2) with an agreement to purchase all of its power output for 20 years – to power its AI data center.

Therefore there is a lot of research into developing computer hardware that is not necessarily faster, smaller, or more powerful but is simply more energy efficient. We are getting to the limits of physics with the energy efficiency of electronic computers, however. Software engineers are also focusing on this issue, trying to create more energy-efficient algorithms. But it would be nice if the hardware itself used less energy. This is one of the big hopes for developing high temperature superconductors, but we have no idea how long or if we will develop anything usable in computing.

The other options is to fundamentally change the way computers work, to rely on different physics. Electronic computers transfer information essentially in the electrical charge of an electron (I say “essentially” to deliberately gloss over a lot of details that are not necessary to discuss the current news item). The current leading contender to replace (or supplement) electronic is photonics, which uses light instead of electrons to transfer information. Photonics are more energy efficient, generate less waste heat, have less data loss, and use smaller devices. Photonic integrated circuits are already being used in some data centers. Photonic computers were first proposed in the 1960s, so they have been a long time coming.

There are also other possible physical phenomenon that could be the basis of computing in the future. The basic science is just being worked out, which to me means that it will likely be a couple of decades, at least, before we see actual applications. One option is spintronics, which uses the spin of electrons, rather than their charge, in order to carry information. Spintronics is also faster and more energy efficient than electronics. Spintronic devices could also store information without power. But they have technological challenges as well, such as controlling spin over long distances. It’s likely that spintronic and photonic devices will coexist, depending on the application, and may even be integrated together in opto-spintronics.

Enter orbitronics – another possibility that uses the orbital angular momentum (OAM) of electrons as they orbit their nucleus as a way of storing and transferring information. The challenge has been to find materials that allow for the flow of OAM. OAM has the advantage of being isotropic – the same in every direction – so it can potentially flow in any direction. But we need a material where this can happen, and we need to control the flow. That material was possibly discovered in 2019 – chiral topological semi-metals, or chiral crystals. Chiral means that they have a handedness, in this case a helical structure like DNA. But in order to work it would need OAM monopoles, which are only theoretical. That is where the new study comes in.

Researchers have demonstrated that OAM monopoles actually exist. They also showed that the direction of the monopole can be flipped – from pointing out to pointing in, for example. These are properties that can be exploited in an orbitronics-based computer technology. The article, which is available at Nature, has the details for those who want to get into the technical weeds.

As always, it’s difficult to predict how potential new technologies will pan out. But we can make optimistic predictions – if everything works out, here is a likely timeline. We are on the cusp of photonics taking off, with projected significant growth over the next decade. This will likely be focused in data centers and high-end consumer devices, but will trickle down over time as the technology becomes more affordable. Photonics, in other words, is already happening. Next up will likely be spintronics, which as I said will most likely complement rather than replace photonics.

Orbitronics, if it pans out, and has sufficient advantages over photonics and spintronics, is likely more a technology for the 2040s, or perhaps 2050s. There is also the possibility that some other new technology will eclipse orbitronics (or even spintronics) before they can even get going.

The post What Is Orbitronics first appeared on NeuroLogica Blog.

Unravelling the complex biological process that allows fish to regrow injured fins could help advance regenerative medicine in humans

Fishers in Albania caught a blue shark with an 18-centimetre fragment of swordfish bill embedded in its skull, in the first known case of a shark surviving such an injury

Highlights from 18 years of the Skeptoid podcast.

A new program has simulated multiple satellites, collecting images of a cloud from many angles at the same time, which could help us to better understand what's happening inside the cloud.

A new program has simulated multiple satellites, collecting images of a cloud from many angles at the same time, which could help us to better understand what's happening inside the cloud.

The hits just keep on coming from the Mars Perseverance rover. It’s exploring Jezero Crater on the Red Planet, looking for evidence of microbial life in the planet’s ancient (or even recent) past. Recently it spotted a very strange-looking rock with black and white stripes. Its appearance and location sparked a lot of questions. Perseverance team members have named it “Freya Castle.”

From the image, this chunk looks remarkably similar to metamorphic rocks on Earth. The most familiar are gneiss, marble, and schist (to name a few). According to Jeffrey Kargel of the Planetary Science Institute, who speculated on what Freya Castle could be, it resembles a very high-grade type of rock similar to what we find here at home. “It looks like and plausibly is, a metamorphic rock containing feldspar or other white-ish minerals arranged in something called boudinage,” he said. “That word stems from French, relating to a chain-link sausage-like structure. In the case of rocks, it forms when you have layered material, usually sedimentary rocks, where the layers are compressed from above under conditions of high heat and pressure. Much of the rock responds plastically squishing down and spreading out.”

Kargel, who is not associated with the Perseverance mission, pointed out that the conditions under which Freya Castle formed on Mars would be similar to Earth’s. “Those conditions have been common on Earth, and erosion then eventually exposes the rocks at the surface. If this is an indigenous Mars rock, it likely would have undergone metamorphism in the lower crust, and then an impact blasted it out, and the rock landed where the rover could examine it,” he said. Other transport possibilities include a deposit by fluid delivery, which makes sense since water has flooded the crater in the past.

An example of gneiss metamorphic rock from Sabino Canyon, in Arizona (USA) as a comparison to the Freya Castle rock on Mars. Courtesy Jeffrey Kargel, PSI. What Kind of Rock Is It?

So, what’s the story with this rock? Based on the image, it looks pretty out of context with much of the dust and sedimentary material in the crater. That makes it worth reviewing the region in a bit more detail. An impact some 3.8 billion years ago carved out Jezero Crater. It lies on the western edge of a large impact basin called Isidis Planitia. A large impact created that basin during an impact about 3.9 billion years ago. At some point in the distant past, water filled Jezero at least twice. There’s a river delta as well as flow channels exiting the crater.

Sedimentary rocks as seen by Perseverance rover at “Enchanted Lake” in Jezero Crater on Mars. Courtesy: NASA/JPL-Caltech

Where there’s water, there’s sediment, which hardens into sedimentary rock. ( The main types of rock are igneous (volcanic or intrusive in origin), sedimentary (deposited by wind or water), and metamorphic.) Not surprisingly, the Perseverance rover continues to find sedimentary deposits and layers at Jezero. The delta is clay-rich, and the crater contains other materials known to be in contact with water. However, some of the rocks in Jezero are also igneous. That means they were created by volcanic activity and somehow brought to the crater.

NASA’s Perseverance rover, which is searching for signs of ancient life on Mars. Some of the rocks in this image are volcanic in origin. (credit: NASA/JPL-Caltech/MSSS)

That brings us back to Freya Castle, which looks metamorphic at first glance. Such rocks have experienced some kind of heat, pressure, or other kinds of geologic stress. That process changed them from one type to another. It also altered the texture of the original rock and the mineral composition.

Creating a Metamorphic Rock

On Earth, metamorphics are a large part of our planet’s crust. They can form deep under the surface where temperatures and pressures are high. Tectonic activity also forces metamorphism. So do impact events. Both heat and compress the surrounding rock. An impact also “excavates” rocks out from deep beneath the surface and tosses them across the surface. Volcanism could be another culprit, sending hot magma into cracks and openings of existing rocks and “morphing” them. Metamorphism can also be the product of the action of hot, mineral-rich fluid injected into other rocks by hydrothermal activity. If that happened, the fluids could have found their way into the layers. The result would be deposits of “intrusive” minerals, resulting in a layered look.

An example of folded metamorphic rock from Norway. Courtesy Siim Sepp, CC BY_SA 3.0

On Mars, all these processes also occurred throughout history. A good analysis of the rock’s minerals could give more details about the mineral makeup of Freya Castle. That would settle the question of what kind of rock it is. Such studies could also give some insight into conditions on Mars at the time it formed.

One thing to keep in mind is that Perseverance looked at Freya Castle with its Left MASTCam-Z camera. A closer study of the rock’s mineralogy and chemistry using its onboard spectrometer could reveal far more information about Freya Castle’s origins. Planetary scientists raised questions about whether the Perseverance team might send the rover back to do a mineralogical study. For now, however, the MASTcam imagery has prompted much speculation.

“If the rock turns out to be metamorphic and from the lower crust of Mars, it might be a very rare opportunity to examine a rock from an extremely ancient period–perhaps a former sedimentary rock that formed when Mars was extremely young, formed as the Martian crust was just developing,” said Kargel. “It might possibly bear evidence of the oldest hydrosphere known on Mars, or anywhere in the Solar System.”

How Did It Get There?

Regardless of its makeup, planetary scientists now need to determine how this unusual rock got to Jezero Crater in the first place. Since the region has been inundated at least twice in Mars’s long history, the most likely interpretation is that it formed elsewhere and was likely blasted out from below the surface during an impact. Then, it got carried along by water. There’s evidence in the Perseverance image of slight rounding of the protruding edges to support the idea of fluid transport. Materials in a flood can get eroded as they tumbled and bounced along in the water. One scientist at PSI suggested that the rounding shows the rock got carried across at least a few kilometers.

At least one “outlier” suggestion is that maybe the rock has an Earth origin. An ancient impact on our planet could have sent Freya Castle out to Mars, where it landed as an Earth meteorite. That’s not a likely origin, however, since the dynamics of getting Earth meteorites out from Earth to Mars are complex.

Freya Castle’s existence at Jezero Crater points out the historical forces that shaped the planet. In particular, it’s a clue toward understanding the complex sequence of events that brought this rock to its current resting place in Jezero Crater. It takes time to analyze those events and the rock itself, which is likely what the Perseverance team is doing as the mission itself continues its trek across the Martian landscape.

Note: Special thanks to researchers at the Planetary Science Institute for discussing specific aspects of metamorphic rock formation with the author.

For More Information

A Striped Surprise
What are Metamorphic Rocks

The post Perseverance Finds a Strange Black-and-White Striped Rock on Mars appeared first on Universe Today.

The general consensus is that Theia crashed into Earth billions of years ago and led to the formation of the Moon. The story doesn’t end there though since there are a few lines of evidence to suggest the Moon could have been captured by the gravitational pull of the Earth instead. The orbit of the Moon is one such observation that leads to a different conclusion for it’s in-line with the plane of the ecliptic rather than the Earth’s equator. A team of researchers have suggested capture theory was the Moon’s origin. 

The Giant Impact Theory is by far the most widely accepted theory to explain the origin of the Moon. In the theory, Theia is thought to have crashed into the Earth 4.5 billion years ago. Following the catastrophic impact, debris from Earth and Theia was ejected out into space and, over time the material is thought to have coalesced to form the Moon. There is a lot of evidence to suggest this, such as the lunar composition which is very similar to the mantle of Earth. 

This image shows what the collision between Earth and Theia might have looked like. Image: Hagai Perets

The data collected from lunar soil samples from over 6 Apollo missions revealed calcium rich, basaltic rocks. The composition was identified by chemical and isotopic analysis and was dated at 60 million years after the formation of the Solar System. Using this information, planetary scientists concluded that, due to the similar with the Earth’s mantle, the Moon must have formed from the collision. That was back in 1984. 

A new piece of research published in the Planetary Science Journal by Darren Williams from Penn State Behrend in Pennsylvania and Michael Zugger from the Applied Research Lab at Penn State proposes an alternative. They suggest that instead, the moon was captured during a close encounter between a young Earth and a terrestrial binary — the moon and another rocky object.

This is not a unique idea though since it has been seen to happen elsewhere in the Solar System. Williams points out that Triton, the largest moon of Neptune may have experienced a similar origin. Triton is thought to have been a Kuiper Belt object that got pulled into an orbit by Neptune. Of the Kuiper Belt objects, 1 in every 10 are thought to be binary objects supporting the theory that the Moon’s formation could well have involved a binary pair. The orbit of Triton around Neptune is retrograde, meaning it moves opposite to the direction of the rotation of the planet. It’s also tilted by 67 degrees to the equator of Neptune. 

Global color mosaic of Neptune’s largest moon, Triton, taken by NASA’s Voyager 2 in 1989. (Credit: NASA/JPL-Caltech/USGS)

The team argue that, even though Earth could have captured an object larger than the Moon, the orbit is unlikely to have been stable. In the capture scenario, the original lunar orbit would have started as an ellipse but, through the effects of tides, been altered. By calculating the tidal changes, the team identify that initial lunar orbit would have contracted over thousands of years, becoming more circular at the same time. It’s this orbit that we see today. 

Now we see the tidal forces causing the Moon to slowly drift away from Earth at a rate of 3cm per year. The team’s calculations showed mathematically that a binary exchange captured satellite may well have led to the behaviour shown by the Earth-Moon system. If this was the case, it doesn’t explain how the Moon formed, just how it came to be a part of our planetary system. 

Source : What is the moon’s true origin story?

The post Was the Moon Captured? appeared first on Universe Today.

Despite decades of large-scale optical surveys, there are still mysteries about the Milky Way galaxy that astronomers are eager to resolve. This is particularly true of its internal structure and the core region, which is difficult to survey due to clouds of gas and dust in the interstellar medium (ISM). This material absorbs visible light, making fainter objects difficult to see in optical wavelengths. Luckily, advances in infrared astronomy have enabled surveys of the Milky Way that have revealed things that would otherwise remain invisible to us.

For more than 13 years, an international team of astronomers has been observing the Milky Way using the ESO’s 4.1-meter Visible and Infrared Survey Telescope for Astronomy (VISTA). In a recently published study, they announced the release of their final data product: a gigantic infrared map of the Milky Way containing more than 1.5 billion objects—the most detailed map our galaxy has ever created! With over 200,000 images and 500 terabytes of data, this map is also the largest observational project ever carried out with an ESO telescope.

Located at the European Southern Observatory’s (ESO) Paranal Observatory in Chile, the VISTA telescope is responsible for mapping large areas of the sky. This latest map contains data gathered by the VISTA Variables in the Via Lactea (VVV) survey and its companion project, the VVV eXtended (VVVX) survey. Led by Dante Minniti, an astrophysicist at Universidad Andrés Bello in Chile, these surveys used the VISTA InfraRed CAMera (VIRCAM) to survey the Milky Way, the Small and Large Magellanic Clouds (SMC, LMC), and extragalactic space.

This spectacular view of the VISTA telescope was taken from the roof of the building during the opening of the enclosure at sunset. The VLT is visible on the neighboring mountain. Credit: VVV Survey/ESO

This latest map contains about ten times as many objects as the previous version, which the VVV Survey team released in 2012. As always, the ability to see the Universe in the infrared wavelength allows astronomers to see objects that would otherwise be obscured by clouds of gas and dust. These include newborn stars embedded in dusty globular clusters, brown dwarfs, and free-floating planets (FFP)—aka rogue planets—that do not orbit stars. “We made so many discoveries, we have changed the view of our Galaxy forever,” said Minniti in a recent ESO press release.

The observations began in 2010, using the camera’s 16 special detectors with a combined resolution of 67 million pixels to survey billions of point sources of light in an area measuring 520 deg2. By observing each patch of sky many times, the team could determine the locations and proper motions of the 1.5 billion objects and monitor them for changes in brightness. The team also tracked hypervelocity stars kicked out of our galaxy’s central region due to gravitational interaction with the supermassive black hole (SMBH) there – Sagittarius A*.

The observations lasted for 420 nights, ending in the first half of 2023. The resulting map provides an accurate 3D view of the Milky Way’s inner regions that were previously obscured by dust. With the surveys now complete, the ESO’s Paranal Observatory is preparing for future surveys by upgrading the VISTA with the 4-meter Multi-Object Spectrograph Telescope (4MOST) instrument. This new instrument will allow VISTA to perform large spectroscopic surveys, capturing the spectra of 2400 objects simultaneously over an area of the sky equivalent to 20 full Moons.

Meanwhile, the Very Large Telescope (VLT) will receive the new Multi-Object Optical and Near-infrared Spectrograph (MOONS) instrument. MOONS consists of two identical cryogenic spectrographs (with 500 fibers each), allowing astronomers to obtain optical and near-infrared spectra for about 1000 objects simultaneously. The combined power of these instruments will provide spectra for millions of the objects surveyed by VVV and VVX, and many more discoveries are anticipated!

Further Reading: ESO, Astronomy & Astrophysics

The post The ESO Releases the Most Detailed Infrared Map of our Galaxy Ever Made appeared first on Universe Today.

You might remember the story of the two astronauts on board the International Space Station that went for an 8 day mission, that was back in June 2024! Butch Wilmore and Suni Williams have been stranded there ever since but their ride home has just arrived at the ISS. A SpaceX Crew Dragon capsule carrying Nick Hague and Aleksandr Gorbunov has just docked so that the two can join the Expedition 72 crew already on board. There are now 11 people on boar the ISS but the Crew-9 capsule will return in February carrying Wilmore and Williams finally back home. 

Being stranded in space sounds like the stuff of nightmares but the reality is a little more mundane….if space travel can ever be classed as mundane! The two astronauts living this reality, Wilmore and Williams have been stuck on board the ISS as a result of thruster problems on the trouble stricken Starliner capsule. Tests were completed, analysis undertaken but the module was autonomously returned home for further tests without the risk to an onboard crew. 

International Space Station. Credit: NASA

Enter the Dragon capsule. Developed by SpaceX, the state of the art spacecraft was designed to ferry astronauts to and from the ISS. It’s been a key part of NASA’s Commercial Crew Program and has been a significant development in the private space sector. One of the key features of the capsule is in its automation, not requiring any pilot to complete its journey but it, if needed, be controlled manually. Somewhat more reliably than the Starliner, the Dragon capsule safely docked and its hatch opened at 7.04pm EDT (23:04 GMT.) 

The Dragon capsule is launched into low Earth orbit by the Falcon 9 rocket. The two stage rocket was also developed by Space X and has operated reliably since its first launch in June 2010. Together with the Dragon capsule, they can deliver crewed and uncrewed missions into low Earth orbit. 

A SpaceX Falcon 9 rocket carrying the company’s Crew Dragon spacecraft is launched from Launch Complex 39A on NASA’s SpaceX Demo-2 mission to the International Space Station with NASA astronauts Robert Behnken and Douglas Hurley onboard, Saturday, May 30, 2020, at NASA’s Kennedy Space Center in Florida. The Demo-2 mission is the first launch with astronauts of the SpaceX Crew Dragon spacecraft and Falcon 9 rocket to the International Space Station as part of the agency’s Commercial Crew Program. The test flight serves as an end-to-end demonstration of SpaceX’s crew transportation system. Behnken and Hurley launched at 3:22 p.m. EDT on Saturday, May 30, from Launch Complex 39A at the Kennedy Space Center. A new era of human spaceflight is set to begin as American astronauts once again launch on an American rocket from American soil to low-Earth orbit for the first time since the conclusion of the Space Shuttle Program in 2011. Photo Credit: (NASA/Joel Kowsky)

The occupants of the Dragon, Nick Hague and cosmonaut Aleksandr Gorbunov joined the 9 existing crew members of the Expedition 72 crew. The astronauts on board are Matthew Dominick, Michael Barratt, Jeanette Epps, Don Petitt, Butch Wilmore, Suni Williams and cosmonauts Alexander Grebenkin, Alexey Ovchinin and Ivan Vagner.

Assuming all goes to plan, Wilmore and Williams will return back with the Dragon capsule in February turning their 8 day mission to an 8 month mission! Fingers crossed for them. 

Source : Expedition 72 Welcomes Crew-9 Duo Aboard Station

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