theoretical physics

Using math to investigate possibility of time travel

Ben Tippett, a mathematics and physics instructor at UBC’s Okanagan campus, recently published a study about the feasibility of time travel. Tippett, whose field of expertise is Einstein’s theory of general relativity, studies black holes and science fiction when he’s not teaching. Using math and physics, he has created a formula that describes a method for time travel.

“People think of time travel as something as fiction,” says Tippett. “And we tend to think it’s not possible because we don’t actually do it. But, mathematically, it is possible.”

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When you think you’re all alone.

When you think nobody loves you.

When you think everything is dark and rotten and there is only sorrow.

You do not know.

You do not know that all around you

in the darkness

there are ninjas.

Not one. Not ten.

Dozens of ninjas.

They feel your pain.

Dozens of ninjas that you do not see.

In the shadows. In the ceiling.

Under the cushions of the couch. They cry beside you.

They wish you well.

nature.com
The quest to crystallize time
Bizarre forms of matter called time crystals were supposed to be physically impossible. Now they’re not.

Christopher Monroe spends his life poking at atoms with light. He arranges them into rings and chains and then massages them with lasers to explore their properties and make basic quantum computers. Last year, he decided to try something seemingly impossible: to create a time crystal.

The name sounds like a prop from Doctor Who, but it has roots in actual physics. Time crystals are hypothetical structures that pulse without requiring any energy — like a ticking clock that never needs winding. The pattern repeats in time in much the same way that the atoms of a crystal repeat in space. The idea was so challenging that when Nobel prizewinning physicist Frank Wilczek proposed the provocative concept1 in 2012, other researchers quickly proved there was no way to create time crystals.

But there was a loophole — and researchers in a separate branch of physics found a way to exploit the gap. Monroe, a physicist at the University of Maryland in College Park, and his team used chains of atoms they had constructed for other purposes to make a version of a time crystal2 (see ‘How to create a time crystal’). “I would say it sort of fell in our laps,” says Monroe.

And a group led by researchers at Harvard University in Cambridge, Massachusetts, independently fashioned time crystals out of 'dirty’ diamonds3. Both versions, which are published this week in Nature, are considered time crystals, but not how Wilczek originally imagined. “It’s less weird than the first idea, but it’s still fricking weird,” says Norman Yao, a physicist at the University of California, Berkeley, and an author on both papers.

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Physicist Create a Fluid With Negative Mass

Physicists from Washington State university have created a liquid with negative mass meaning that when you push it, instead of accelerating in that direction, it accelerates backwards.

Matter can have a negative mass much the same way that particles can be negatively charged. Newton’s second law of motion (F=ma) tells us that mass will accelerate in the direction of the force so we can deduce that matter with a negative mass would do the opposite and accelerate against the force.

To create the conditions for negative mass, Peter Engels and his team started by cooling rubidium atoms to a Bose-Einstein condensate meaning they reached very near absolute 0. The researchers used lasers to trap the atoms in an area less than 100 microns across and allow high energy particles to escape cooling them further. Then to create negative mass, the physicists applied a second set of lasers to change the way atoms spin back and forth. They then removed the first set of lasers causing the rubidium to rush out and appear to hit some sort of invisible wall; behaving as if it had a negative mass.

What’s great about this is the control we have over the negative mass without any other complications. This gives us a new tool we can use to engineer experiments in astrophysics looking at neutron stars, black holes, dark energy and a lot more.

Three Badass Subfields of Astronomy: Astrobiology, Astrochemistry, and Astrophysics

I’ve been receiving a lot of messages from people curious to know the differences between these subfields of astronomy. So, I’ve written a post giving a simple definition and a brief description of what’s involved in each.

Astrobiology (also known as exobiology) is the study of the origin, evolution, and distribution of life here on Earth and—more importantly—the entire universe. Using existing origin theories and models, this relatively new branch of astronomy is primarily focused on analyzing and discovering the amazing possibility of extraterrestrial life.

Astrobiologists face some distinct problems in their work. Many planets are completely unsustainable to life as we know it. Scorching or freezing temperatures, seemingly gentle rain that would actually burn the skin off of your body, or hurricanes the size of Earth itself are quite common planetary conditions in the universe. Astrobiologists attempt to simulate the possibilities of life cropping up in these unlikely conditions. Whether or not a life form can survive in these types of environments will reveal just how diverse and adaptive it is. Despite nature seeming like a sadistic asshole, there is striking evidence for the resilience of life. Astrobiologists have outlined four requirements for life to survive:

  1. A liquid solvent in which molecules can move freely and interact. 
  2. An energy source.
  3. An atom which allows complex structures to exist.
  4. A sh*t load of time.

Considering that certain life forms here on earth have defied some of these requirements, it’s logical to presume that there is indeed extraterrestrial life. The fact that the conditions can literally be terrible and life can still survive, is enough to convince me there are almost certainly other forms of life in the universe.  

Additionally, if we do find evidence of other life forms in the universe, they will probably look almost nothing like little green men with large heads and telepathic abilities (although, that would be awesome). In fact, astrobiologists hypothesize that extraterrestrial life will most likely be far more exotic and diverse than anything we can possibly imagine. Nature has certainly shown that it has one hell of an imagination.

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Superfluid Helium

It was previously thought that superfluid Helium would flow continuously without losing kinetic energy. Mathematicians at Newcastle University demonstrated that this is only the case on a surface completely smooth down to the scale of nanometers; and no surface is that smooth.

When a regular fluid like water is passing over a surface, friction creates a boundary layer that ‘sticks’ to surfaces. Just like a regular fluid, when superfluid Helium passes over a rough surface there is a boundary layer created. However the cause is very different. As superfluid Helium flows past a rough surface, mini tornados are created which tangle up and stick together creating a slow-moving boundary layer between the free-moving fluid and the surface. This lack of viscosity is one of the key features that define what a superfluid is and now we know why it still loses kinetic energy when passing over a rough surface.

Now we can use this information to help our efforts on applications of superfluids in precision measurement devices such as gyroscopes (I think this was on the Big Bang theory where they make a gyroscope using superfluid Helium that can maintain angular momentum indefinitely because it would flow across a smooth surface without losing kinetic energy) and as coolants.

anonymous asked:

i've discovered the greatest wiki page ever and it's the muppet wikia page for 'the universe'

the seamless integration of real-life theoretical physics and fraggle rock lore as if there is no border between the two whatsoever. oh my god

Strange Shit That Has Happened On Game Grumps And Isn’t Even Discussed
  • Barristan Selmy from Game of Thrones opens a random episode for no apparent reason and with no explanation
  • Arin scream-sings Circle of Life in a public place
  • The fucking ads are the stuff of nightmares
  • Rob Schneider comes on Game Grumps after Arin completely rips apart his tv show for a full episode
  • Arin opened a set of 10 or so episodes with monologues about following his twitter, cooking your own food, that he’s really a bat portraying the character of Arin Hanson, that his editor is too handsome, he wants to sell out to Wendy’s, and then hits himself as hard as he can with a plastic bat. This is giffed but not commented on.
  • Chris Pratt likes the Super Mario Galaxy playthrough, confirms he is a melon with his name written on it.
  • Arin assembles what looks like a several hundred person mob to go to a random Wendy’s in Ohio, because he wants to sell out to them but they won’t return his tweets. 
  • They’ve got a fucking TV show coming out with the guys from Rick and Morty? Why is this not mentioned more?
  • L o v e l y  d a y  f o r  c r i c k e t 
  • Arin and Ross abused the ‘give a free ride get a free ride’ code on Uber by sending theirs out to 3.5 million people. Reportedly, Arin now has over 800 free rides.
  • Ross and Barry sold their pokemon fanart in an art gallery.
  • Seriously the fucking ads? In one of them Barry is turned upside down while Arin growls in a corner and then time-lapse punches Barry into a wall, and this is an advert for Lootcrate
  • Dan repeatedly hit a two pound gummy bear against a table to try and remove its head
  • A professor of theoretical physics quit his fucking job to do the show
Physicists may have fallen prey to a false dichotomy between mathematics and physics. It’s common for theoretical physicists to speak of mathematics providing a quantitative language for describing physical reality… But maybe… math is more than just a description of reality. Maybe math is reality.
—  Brian Greene, The Hidden Reality

boom-kaka-laka  asked:

Hey :) I don't want to be annoying or anything but I was wondering if you could recommend some books or websites were I could learn more about space.. I have huge interest in it but I don't really know much about anything from the astro field >_<

Since space always has a bunch of crazy shit going on in it, I’ll just take a bunch of random bookmarked links I have and throw them at you!

Books:Videos:Space Image Galleries: Cool Online Programs:Random Articles: