Tag Archives: vacuum

What is the vacuum of space?

In The Private Journal of Henri Frederic Amiel, the famed philosopher stated that “Uniformity [..]creates a void, and Nature abhors a vacuum.” However, most astronauts have probably been aware of the fact that their surroundings are, in fact, a vacuum.

This then might beg the question, “why is there a vacuum in the first place?”

The cosmos is mostly empty, but it’s not really empty. Image credits: Jeremy Thomas.

First, lets get rid of a misconception. When you think of a vacuum, one generally thinks of something with a lack of air. One fun way to try this is to take an empty bottle and just try sucking all of the air out. If you could do that perfectly (spoiler alert, you can’t), you would creat a vacuum inside the bottle, which makes it stick to your lips. As long as the mouth of the bottle doesn’t have any spaces between it and your lips, it will give you the ability to swing it around with your head as you please, also giving you the ability to attract annoyed stares from your wife.

However, if you think of it way, space is not a true vacuum; there really isn’t such a thing as a vacuum.

Emptiness

The word stems from the Latin adjective vacuus for “vacant” or “void”, however, there is a whole lot of stuff actually filling space what we consider the vacuum of space.

“(W)hen we say outer space (the space outside the atmosphere of planets and stars) is a ‘vacuum’ or is ‘empty’, we really mean that outer space is nearly empty or almost a perfect vacuum,” explains Dr. Christopher S. Baird, an Assistant Professor of Physics at West Texas A&M University, in his blog Science Questions with Surprising Answers.

“In reality, even the most remote spot of outer space has gas, dust, radiation, gravity, and a whole host of other things. There is no such thing as truly empty space. If we tried to suck all the particles out of a certain volume, we could still never get it empty. There would still be things like vacuum fluctuations, gravity, and dark matter, which can’t be sucked out. With that said, outer space is very close to empty compared to earth’s atmosphere.”

Ancient Greeks had some interesting ideas about vacuums — as they did with most things. They didn’t know what an atom was, but they considered the idea of atomism: small things that fill everything. The abstract concept of a truly empty void was regarded with skepticismm, even as Plato lent some support. His disciple Aristotle believed no void could occur naturally, because the denser surrounding material would simply fill up the setting

Almost two thousand years after Plato, René Descartes also proposed a theory similar to atomism, but without the problematic matter of the void. Descartes also agreed with the contemporary position that a vacuum does not occur in nature.

Yet to this day, the idea of a vacuum remains somewhat uncertain among physicists — especially with concepts such as dark matter and dark energy in the mix.

Making a vacuum

Image credits: JD Hancock.

This still hasn’t exactly answered the question of “what causes the vacuum” though.

The short answer is that in the void of space, the pressure is so low that all molecules want to spread out as much as possible. This expansion, in turn, creates the vacuum that we all know to exist, and is also what leads to the development of the stars and planets that we see in our night sky.

Because outer space has very low density and pressure, it makes something very close to a vacuum — but it’s still not a perfect vacuum. Even in interstellar space, there are still a few hydrogen atoms in every cubic meter.

“Every particle of matter, no matter how small, exerts a gravitational attraction on all other particles of matter,” says Baird. “Given enough time, gravity makes giant clouds of gas in space condense down despite the gravitational force being so weak. Soon after the Big Bang, the universe was filled with a nearly uniform soup of hydrogen and helium. Over billions of years, gravity pulled most of these gas atoms into stars. Inside the nuclear furnace of stars, hydrogen and helium were fused to form the heavier elements up to iron.”

Larger stars will eventually die in an explosive supernova creating all the naturally occurring elements heavier than iron and spewing these elements into space. Over the course of time, the heavier elements condense down under gravity to form small clouds and rocks. In turn, the clouds and rocks are gravitationally attracted one other which will form asteroids, moons, and planets. Space is mostly empty because matter that used to be out there has fallen into an asteroid, planet, moon, or star under the influence of gravity.

Another misconception is that exposure to a vacuum leads to instantaneous death. Being exposed to the vacuum can actually be survivable, albeit very uncomfortable.

A 1965 study by scientists at the Brooks Air Force Base in Texas showed that dogs exposed to near vacuum—one three-hundred-eightieth of atmospheric pressure at sea level—for up to 90 seconds always survived, however, during the exposure, they were rendered unconscious and paralyzed.

They also experienced serious discomfort as gas expelled from their bowels and stomachs caused simultaneous defecation, projectile vomiting and urination while also suffering massive seizures. Their tongues were often coated in ice and the dogs swelled to resemble “an inflated goatskin bag,” the authors wrote. But after slight repressurization the dogs shrank back down, began to breathe, and after 10 to 15 minutes at sea level pressure, they managed to walk, though it took a few more minutes for their apparent blindness to wear off.

“In any system, there is always the possibility of equipment failure leading to injury or death,” says Dartmouth Medical School professor and former NASA astronaut Jay Buckey, author of the 2006 book Space Physiology. “That’s just the risk you run when you are in a hostile environment and you depend upon the equipment around you. But if you can get to someone quickly, that is good. Often spacewalks are done with two spacewalkers and there is continuous communication. So if someone is having a problem, hopefully the other can go get them and bring them in.”

A real-life example occurred in 1966 when NASA engineer Jim LeBlanc was accidentally exposed to a near zero vacuum.

The space suit he was testing experienced a rapid loss of suit pressure due to equipment failure. He recalled the sensation of saliva boiling off his tongue before losing consciousness.

When the chamber was rapidly repressurized, LeBlanc regained consciousness quickly and went home for lunch. Another man was accidentally exposed to vacuum in an industrial chamber; it was at least three minutes before he was able to be repressurized. He required intensive medical care, but eventually regained full function. These instances show that ebullism — the formation of gas bubbles in bodily fluids due to reduced environmental pressure — is not inevitably fatal and the body can hold together just fine…at least for a few seconds.

Credit: : Tongcang Li/Purdue University.

Scientists devise world’s fastest spinning object — a tiny dumbbell that spins 60 billion times per minute

Credit: : Tongcang Li/Purdue University.

Credit: Tongcang Li/Purdue University.

A nano-dumbbell, made of two joined silica spheres and only 0.000007 inches wide (170 nm), is the fastest man-made rotor in the world. Researchers at Purdue University spun the rotor a staggering 60 billion times per minute, which is about 100,000 times faster than a high-speed dental drill.

Apart from being an extraordinary feat of science and engineering, the observations of the rotor’s behavior could shed new light on exotic physics, such as quantum mechanics.

“This study has many applications, including material science,” said Tongcang Li, an assistant professor of physics and astronomy, and electrical and computer engineering, at Purdue University. “We can study the extreme conditions different materials can survive in.”

In the past decade, scientists have pushed the limits for the fastest spinning rotor farther and farther with each new iteration. In 2008, the record belonged to a matchbook-sized rotor, which clocked 1 million rotations per minute. In 2010, a new record was set when scientists spun a slice of graphene at 60 million rotations per minute. Later, in 2013, a sphere measuring just one-tenth of the width of a human hair completed a staggering 600 million spins per minute.

Now, Li and colleagues have shown that it’s possible to rotate things even faster. Following the miniaturization trendline, the researchers synthesized a tiny dumbbell from silica and levitated it in a vacuum using a laser, which fired circularly polarized light. The polarized light forced the dumbbell to spin and — since there were virtually no air molecules to slow it down — it did so furiously fast, clocking 60 billion rotations per minute.

A second laser that fired linearly polarized light made the dumbbell vibrate and confined the tiny device to the same plane.

The physicists hope that their experiments might help them understand vacuum and gravity better and, ultimately, some quirks of quantum mechanics.

“People say that there is nothing in vacuum, but in physics, we know it’s not really empty,” Li said. “There are a lot of virtual particles which may stay for a short time and then disappear. We want to figure out what’s really going on there, and that’s why we want to make the most sensitive torsion balance.”

The findings appeared in the journal Physical Review Letters.

Ilife V8 robot.

Product Review: iLife V8 Smart Robotic Vacuum

Chinese manufacturer iLife is back with a new flagship robot vacuum — the V8. But is this something that should interest you? After a week toying around with the bot, I think it should.

Ilife V8 robot.

Image credits Mihai Filip / Shotworks Photography.

It’s not perfect. It’s possibly not the most innovative or flashy robot vacuum out there, either. But the V8 digs down to the core identity of iLife’s products — good value — and doubles down on it. If you’re looking for a robot that will vacuum and mop with very little oversight on your part, the V8 is right down your alley. With a $250 price tag, it will be right down your wallet as well.

The design

For the V8, iLife stays true to the design principles it set down with its ‘A’ series — personally, I fell that they made the right choice. It sports a sleek, two-colored body with a touch of minimalism. It’s quite pleasant to see it go about its business through the house. The tried-and-true front bumper got a subtle redesign but is just as effective at protecting the bot from any eventual blunderings.

Its topside sports 5 buttons — power, home, schedule, spot cleaning and a mapping button — and a screen display for time and battery level. The underside houses the wheels and cleaning implements (more on that later).

The unboxing

It comes packed with two sets of cleaning brushes — including a tangle-free rubber brush that will become your best friend if you own pets — a dustbin for vacuuming, and HEPA filters. Should you be in the mood for (avoiding) some moping, the bot can be fitted with a water tank and two sink-washable microfiber cloths. The charging dock, power cable, user manuals, and remote control are also included in the package. You will need separate batteries for the remote.

Now onto the meat of it.

How well does it work?

The V8 outdoes its older cousins such as the A4 in raw power. Its vacuum is brawny enough to remove impressively-looking pieces of debris. The dustbin is large enough, at some 750 ml (25.3 fl oz), that you don’t have to empty it after every round. In my case, it hoovered up some 10 grams (0.35 oz) of dirt after every run. It has to be noted that my flat sits on the side of a major boulevard, and it gets really dusty.

V8 bottom.

Image

It was also very determined in going over anything I’ve put in front of it — only refusing to cross bunches of wires or particularly fluffy rugs. The last bit is actually not a bad thing: you can leave the floors in the V8’s care, knowing that it won’t get stuck on something it can’t cross. The bot is also slim and reaches under most furniture, so you don’t have to do any heavy lifting while it goes about its day.

Although I don’t consider mopping a central requirement for a robot vacuum, it’s a nice feature to have. The V8 also does it well. It will keep tabs on the amount of liquid permeating the cloth so it’s never too wet or too dry.

Something I do consider very important in such a device, however, are collision sensors and pathing options — the V8 carries itself well in both regards. It is one of the few such robots on the market with a ‘brain’ to help it self-navigate around rooms and a 360° live camera to help it avoid obstacles. It will softly bump into stuff sometimes to see if it can push it out of the way — which I always find funny. Should it fail that, it will just back off and move on. But it won’t drop down a flight of stairs, or from a tabletop, if you decide to put it there in the first place.

V8 pathing.

The robot will try to use a systematic approach to cover all floor surfaces — but it will improvise when a piece of furniture blocks its way. Image credits iLife.

It has two pathing options, and an inbuilt gyro array to ensure it stays true to its path. The redesigned remote also allows you to point at any spot you want the V8 to clean — very handy.

Its battery will last for a very good 2 hours at a time, taking 3 hours to fully recharge. When the battery runs low it will put its current tasks on hold, head to its charging station, and wait for the battery to refill.

Compared to previous iLife robot vacuums, the V8 also inches ahead in regards to cleaning speed.

What you should not expect

The ‘jack of all trades, master of none’ brand is quite appropriate for the V8. It will do a good job of cleaning your house, with the obvious limitations inherent to robotic vacuums. It will both mop and vacuum with enthusiasm — making it good, but not perfect, at either task. For example, it just doesn’t have the mass to scrub floors like a dedicated mop. But in a maintenance role, it holds its own against competitors.

The two main issues the V8 has are a lack of programmable barriers or a recharge & resume function. They are, however, quite minor problems in my view. My place isn’t very large, so the lack of barriers wasn’t actually an issue. Should you live in a mansion, however, your mileage may vary on this one. The recharge and resume function, in my eyes, is more of a flashy quirk. The bot will resume its duties from the charging station after topping off its battery, so it’s not something you really need.

If you really want those features, however, the V8 might not be for you.

Additional goodies

The V8 also comes with a voice alert assistant system that scared the bejeezus out of me the first time I heard it. However, it can be configured to keep you updated on the robot’s state — such as its battery level and the expected time of its job completion. You also get voice control options, so you can prompt the V8 to detail its current condition.

It’s the first iLife robot vacuum that has its own app. This allows you to track its movement in real time, or see where it plans to go clean next.

Finally, the remote control gives you complete control over the robot. You can schedule cleaning, choose cleaning modes, or prompt the unit to return to its charging station without even getting out of bed.

Would I recommend it?

Yes. It’s neither a perfect vacuum nor a perfect mop but it’s a good vacuum-and-mop. It will vacuum all but the most stubborn of messes and the mop functionality is good enough to keep floors in good condition.

A generous battery capacity coupled with solid hardware and software makes it very low-maintenance. Multiple features make it a versatile and convenient device and operating it is a breeze. It has a longer running time than competing robots and is more powerful than its older cousins from iLife.

With a price tag of only $250, this is a very attractive buy — probably the best if you’re shopping on a budget.

How the water bear defies death even in the vacuum of space by wrapping its cells in glass

Tardigrades are the toughest, most resilient animals we know of. They can survive temperatures from 1 K (−458 °F; −272 °C) to about 420 K (300 °F; 150 °C), pressures six times greater than those found in the deepest ocean trenches, ionizing radiation at doses hundreds of times higher than the lethal dose for a human, and the vacuum of outer space. One tardigrade female was brought back to life after being frozen for 30 years then birthed 14 healthy babies. 

Water bear don’t care

Simply put, the tardigrade, also known as the water bear, is the most extreme survivalist out there. If there’s an animal that knows how to make it against all odds, it’s this guy and, as you might imagine, a lot of people are interested to find out what its secret weapons are.

The water bear is able to withstand such extreme conditions by going into a sort of safe mode, as it dries up into a little barrel called a tun. In this form, neither heat, cold or the wretched vacuum of space can kill it. Essentially, the tiny bear which is smaller than 1 millimeter enters a state called anhydrobiosis during which the metabolism shuts down.

Now, researchers from the University of North Carolina at Chapel Hill have found another ace up the water bear’s sleeve. During a dry spell when water is scarce anti-dehydrating proteins called tardigrade-specific intrinsically disordered proteins (TDPs) become vitrified. When this happens all the tardigrade’s dehydration-sensitive tissue and cells become protected by a glass surface. This way, sensitive proteins and other biological molecules are locked in place. They can’t fold, they can’t break apart nor can they aggregate together, which explains how the animal can survive in space and then come back to life like nothing happened within an hour.

The video below shows how much the water bear shrinks when deprived of water.

https://www.youtube.com/watch?v=09U9tc-aaek

The team led by Thomas Boothby intentionally subjected the tardigrades to conditions that would force them to dry out. Meanwhile, they carefully monitored the animal’s gene activity. Boothby and colleagues noticed a spike of activity in a group of genes when the TDPs were produced. When such genes were blocked through genetic engineering, the tardigrade died of dehydration.

When bacteria and yeast were artificially infused with the aforementioned genes, these became much more resilient in the face of dehydration. This remarkable experiment suggests that, at least partly, the tardigrade’s tricks can be passed down to creatures. For instance, one interesting idea would be to produce new genetically modified crops that carry TDP genes to help them survive droughts. California’s worst drought in history, which is still not over and sure as heck isn’t the last, serves as a reminder that such crops are badly needed.

Previously, a 2008 study concluded that the tardigrade’s anhydrobiosis is linked to specialized sugars called trehalose. Tree frogs use the same sugar molecules to come with dry environments as well but not everyone was convinced the water bear uses the same mechanism because the study could only find trehalose-linked processes in only one species of tardigrade. Indeed, Boothby found tardigrades either don’t make or make very little amounts of trehalose.

It’s amazing however that TDPs work much in the same way as trehalose — they both protect cells by forming literally glass structures. So, what we’re essentially dealing with is yet another textbook example of convergent evolution — two animals (tardigrade and tree frog) totally unrelated from each other who evolved the same adaptive trait.

Another water bear trick involves using other proteins to shield its DNA against radiation. A previous research found  17.5 percent of a tardigrade’s genome was comprised of foreign DNA, including genes from bacterial species that can withstand extreme pressure and heat.

Next, the researchers plan on investigating other animals and even plant seeds which seem to survive desiccation to see whether they use the same proteins. Besides drought-resistant crops, such investigations might one day lead to amazing practical applications. One immediate application could be a new medium for storing vaccines and pharmaceuticals at room temperature by using dehydration instead of refrigeration. A much farther away application might involve dehydrating people to induce a hibernation-like state, which could be useful in interstellar flight.

tardigrade gif

Journal ref: T.C. Boothby et al., “Tardigrades use intrinsically disordered proteins to survive desiccation,” Molecular Cell, doi:10.1016/j.molcel.2017.02.018, 2017.

Product Review: ILife Beetles A4 Smart Robotic Vacuum Cleaner

Ah, chores. Some people hate them, and I hate them even more. So you can imagine my joy when we got a smart robotic vacuum! Now we had someone to keep the place clean while we languished around like kings. That vacuum is the ILife Beetles A4, courtesy of our friends from GearBest, and I’m here to tell you all about our experience with it.

DSC_5361-2

The unboxing

They say don’t judge a book by its cover but this isn’t a book and it looks awesome. We got the one in metallic gray and while the overall shape and design aren’t that different from other robot vacuums on the market, it’s sleek, elegant and looks really nice.

The front half of the robot is fitted with a bumper so that when it inevitably runs into furniture on its first few runs, neither will be damaged. And just to be extra safe, there’s an added layer of cushioning in the form of a soft rubber band all around the bumper. On the underside, the A4 has its motor and driving wheels, two sets of cleaning brushes (a pair of side brushes to sweep the floor and one larger drum brush to scoop everything up) a set of IR sensors and the dust bin.

The device comes with a manual, a remote, and a spare filter and side brushes. You’ll also find its charging station and the tools you can use to clean and maintain the bot in the box.

The first thing we did was let it charge overnight.

So how does it run?

We didn’t even read the manual before our trial run, but thankfully the device is pretty intuitive to use. Once you power it up all you have to do is press the “Clean” button on the top cover and the robot will take care of the rest. We watched it cleaning the floor and bumping into stuff for about 10 minutes. It’s slim enough to get under almost any piece of furniture, and it left a very satisfying line of cleanliness behind it. We folded some pieces of paper to test what it could pick up and, apart from chunky pieces of trash or stuff that we embedded in really fuzzy mats, it got everything on the first go. The side brushes can sometimes throw pieces of thrash away but if you leave the A4 to its own devices it will eventually scoop these up too. It handles dust and pet hair very well and doesn’t blow them up all over the room, either.

The A4 does have some difficulty navigating cables — more exactly, if you happen to have a lot of cables on the floor, the robot will snatch them up with its wheels. It will register them as an obstacle and move eventually, but it will drag the cable after it.

On its second run (so this would be around 15-20 minutes of use in the same room) it started to follow the outline of the furniture neatly, though by this time the cats started hunting for it and giving it all kinds of trouble — so we decided to test the IR sensors. The A4 model comes equipped with “Intelligent Drop Avoidance Induction,” a system that relies on the sensors on its underbelly to stop the robot if it reaches a high gap so it won’t fall to its doom — pretty handy. So we cleared a desk, put the bot on it and let it reach every margin a few times, but it didn’t fall once.

By now we were pretty happy with how it moved and cleaned so we wanted to test its cleaning modes. There are a lot of different settings you can pick — we settled for the scheduled auto cleaning mode and automatic re-charging. This is the most versatile mode, and it allows you to set a time each day when the A4 will leave its station and clean everything in sight, then come back to re-charge.

The robot’s battery is powerful enough to allow it to clean our (two-bedroom) flat in one go. Truthfully I don’t know how much it takes the little thing to recharge after — it does it all by itself. But if something’s bothering it it’ll let you know — the “Clean” button will flash orange if it’s low on battery or recharging, and a red flashing light means it’s run into an error. As long as the button’s green, you know it’s fine and going about its business.

DSC_5357-2

Oh, and it’ll even tell you — the bot is programmed to let you know, via some seriously cute beeps, about how it’s doing — such as accepting a command or routine problems it could run into. The tones are covered in the instruction manual.

Maintenance

The 0.45 L (15.2 oz) dust bin is big enough that you don’t have to clean it daily. However, if you plan to use the A4 in an environment that hasn’t been vacuumed in a while, I suggest you empty the bin a few times until it’s been all over the floor. Cleaning the bin is really simple and fast. It takes me around 30 seconds to do it.

The charging IR sensors and charging station’s pins should be cleaned regularly. I do it once a week just to be sure, but it really depends on how dusty your house tends to get.

One of the more time-consuming maintenance steps is cleaning the main brush. This can become a problem if you have pets that shed hairs (and/or long hair yourself) which can get caught in the main brush. The robot will still work but it’s gonna be harder for it to scoop up all the stuff on your floor. We had to do it after the bot’s first run when it got really tangled but after that, I found that once a week is often enough. Thankfully, removing the brush is really easy and straightforward.

DSC_5362-2

So would I recommend it? Yes, I would. It’s a solid design and the price-to-quality ratio is really good. Unless you have 50 cats and all your floors are covered in rugs it will get the job done. Just pick up the larger debris yourself and it will take care of the rest.

You can buy the ILIFE A4 Smart Robotic Vacuum Cleaner for $146.99 from GearBest.

Credits to Mihai Filip Alexandru for the photographs.

 

speed-of-light

Speed of light may fluctuate in vacuum, controversial studies suggest

Since Einstein first postulated his theories of general relativity, physicists have constructed models describing the Universe that mainly revolve around the idea that the speed of light is constant through vacuum. Two new studies, yet to have been published in peer-reviewed journals, suggest that light through vacuum actually fluctuates, albeit the deviations are infinitesimal. Still, if their new studies hold valid, then some ideas would require refinement, while a  caveat that states that the speed of lighet varies would need to be included.

speed-of-lightOne of the two papers is authored by Marcel Urban and colleagues  from the Univ. of Paris-Sud, who claim they have identified a quantum level mechanism for interpreting vacuum as being filled with pairs of virtual subatomic particles with fluctuating energy values. Though seemingly utterly empty, an intriguing concept in physics holds that vacuum is filled with continuously appearing and disappearing particle pairs such as electron-positron or quark-antiquark pairs. The lives of these subatomic particles is extremely short, however it may be enough to cause a displacement in the speed of light.

The team lead by Urban have created a detailed quantum mechanism that would explain the magnetization and polarization of the vacuum, referred to as vacuum permeability and permittivity, and the finite speed of light. In other words, the speed of light might depend on the properties of vacuum.

In the secondly discussed paper, Gerd Leuchs and Luis Sánchez-Soto, from the Max Planck Institute for the Physics of Light in Erlangen, Germany complement the findings of the first paper and claim that the speed of light and the so-called impedance of free space, are indications of the total number of elementary particles in nature.

If found valid, though, these fluctuations would be minuscule. Just how tiny? Well fluctuations in time are estimated to be somewhere around the realm of 50 attoseconds per square meter, where an attosecond is one quintilllionth (10^-18) of a second. Just so you can get a better idea one attosecond is to a second what one second is to 31.71 billion years and 320 attoseconds represent the require time for electrons to transfer between atoms.

Even so, traveling from extremely vast distances across, like light emitted from the early Universe, light might become visibly slowed down.  The two studies will first need to survive further vetting since both have yet to finish the peer-review process.

 source: Alpha Galileo Foundation