Levitating liquids with sound – video

Such a simple and beautiful idea. Liquid drops are suspended at the nodes of a sound standing wave. Applications in simulating microgravity and in manipulating drugs without touching them. More details here: http://www.anl.gov/videos/acoustic-levitation


Interview “The Avengers” film and superhero science

1. How realistic, would you say is it that anything in the Avengers could actually happen?

Iron Man’s suit is within the reach of current technology. A number of research institutions across the world are developing powered exo-skeleton suits to increase the strength of the wearer. For example Tsukuba University in Japan has developed the HAL suit (hybrid assistive limb) for use by rescue workers as it can increase the muscle strength by 5 times. Hospitals are also interested in using it to rehabilate patients and for increasing the capabilities of disabled people.

Military Pilots now routinely fly with helmets that contain information, communication and augmented reality technology much like Iron Man’s helmet. The latest innovations give the pilot “x-ray vision” through the floor of the plane or helicopter. This is achieved by tracking the pilot’s head movements and projecting onto the helmet’s visor the correctly orientated video images from cameras on the outside.

The giant S.H.I.E.L.D  Helicarrier can turn invisible using stealth technology. One way this could be achieved would be to cover the hull of the ship with a vast array of Light Emitting Diodes that can be used to display images onto the outside of the ship. If the image matches the background the Helicarrier would appear to be invisible or at least have some degree of camouflage. The car manufacturer Mercedes recently produced a viral video of one of their cars turning invisible using this approach.

2. Which character portrays scientific elements most realistically? For example Tony Stark’s inventions, Bruce Banner and Dr Erik Selvig as scientists?

For me the most realistic science comes from Tony Stark’s inventions. The Iron Man suit consists of elements that either exist today or are in development; from rocket powered jet suits through to light weight body armour.

I have problems with the science around Bruce Banner changing into the Incredible Hulk. Gamma radiation does indeed cause changes in a creature’s genetic code however the changes almost always cause damage to the cell that results in death or severe damage. I have seen no evidence to support the idea that radiation causes dramatic mutations; whether that’s two headed fish swimming around nuclear powerplants or superhero stories like the Hulk, Spiderman and Fantastic Four.

Dr Eric Selvig is an astrophysicist. In both Thor and the Avengers the Tesseract opens a portal or “worm hole” between vast distances in space or even between different universes. In physics there are theories that “worm holes” can exist that link two points in space that are separated by a large distance. These theories are one solution from equations describing how space is curved by massive objects; equations first developed by Albert Einstein in 1915. However, there is no evidence to show that worm holes exist and the majority of current scientists don’t believe they do exist. Even if they do, it’s unlikely that humans would ever be able to see them, let alone control them.

3. With Thor being a God how effectively does he fit in to this universe and does he have any scientific link/background to him?

Thor travels through a “worm hole” that links Asgard to Earth even though there’s a vast distance between the two planets. Worm holes are often used as plot devices in science fiction stories. They are theoretically possible as a solution to Einstein’s famous General Relativity equations however most scientists do not believe they exist as they create a number of paradoxes.

Thor is also known for his incredible strength which could be caused by his race evolving stronger muscles and bones rather than him being a God. I have problems with how he uses his hammer though as quite often it defies the laws of physics. When he hits people with the hammer they go flying, however when he magically attracts it back to his hand at great speed it doesn’t knock him backwards as it should do.

4. Bruce Banner’s transformation into the Hulk is rather drastic, is there any link between mood and transformation?

When humans are scared or get angry the body starts producing chemicals like adrenaline which get the body ready for ‘fight or flight’. The heart rate and breathing increases and blood is directed towards the muscles. The person’s pain tolerance increases, reactions become faster and they become more aware of the surroundings. You can see the response in the person’s eyes as the pupils become dilated. There isn’t a dramatic change like the Hulk but there is a link between our mood and our body. And it works both ways! Try taking fast short breaths and you might find yourself feeling scared. And now try taking slow deep breaths and see if you feel more relaxed.

5. Talking about Captain America, his Shield is of great importance and is made of the Marvel universes ‘Vibranium’ how likely is it that a metal/substance like this could actually exist or be produced in the future?

Any object that hits Captain America’s “Vibranium” shield, like bullets, are stopped dead in their tracks. When two objects collide you need to take into account two things that need to be conserved: the energy and momentum.

Moving objects have an energy associated with them called kinetic energy. Bullet proof armour is designed to dissipate the energy of the projectile into the armour rather than the human body. You want the threads that armour is sewn from to be both strong and have the ability to stretch. The best man made material at the moment is called Kevlar although it is inferior to the toughness of spider silk. It may be possible that Captain America’s shield is excellent at dissipating energy but this doesn’t help with the projectile’s momentum.

The heavier and faster an object moves, the more momentum it has. (Being hit with a golf ball is much more painful than being hit by a ping pong ball.) When a projectile hits a stationary target, some of momentum is transferred across causing the target to be knocked backwards. A person who is shot by a bullet is still knocked backwards. In the Avengers film Captain America’s shield is repeatedly hit by objects with a lot of momentum but he successfully deflects them without being knocked back.

6. The film focuses greatly on The Tesseract, but what exactly is it and how is it supposed to work?

The Tesseract, or the Cosmic Cube, is described as a source of unlimited power. In the Captain America film it was used by Red Skull to create incredibly destructive weapons and in Thor and the Avengers it was used to open a Worm Hole between two points in space separated by a vast distance. In the Marvel universe it is also said to be able to evolve its own intelligence from the energy contained within. The science explanation in both the comics and films is somewhat lacking. The Tesseract is meant to be a multi-dimensional object that contains the energy trapped within. The name comes from a shape in geometry that is the 4 dimensional analog of a cube, just as a cube is a 3 dimensional analog of a square.

A very active area of research in particle physics is concerned with trying to link together the extremely large scale effects like gravity and the tiny scale effects of quantum mechanics. One approach is String Theory which describes how our universe is not made of the 3 dimensions that we’re used to seeing but 10 or more dimensions. If this is true, there’s a lot going on in the universe that we’re unaware of and maybe, as some science fiction writers have suggested, there’s some hidden energy source that we can tap into.