- Title: Black hole in a 'bathtub' makes waves for UK scientists
- Date: 21st August 2017
- Summary: NOTTINGHAM, ENGLAND, UK (JULY 12, 2017) (REUTERS) WATER BATH WITH WATER DYED GREEN WITH PATTERN PROJECTED ON SURFACE / DARKER DYE BEING ADDED AND SPIRALLING TO CENTRE WIDE OF WATER BATH AS DYE SPIRALS CLOSE OF 'BLACK HOLE' IN WATER WIDE OF WATER BATH WITH RESEARCHERS THEO TORRES (LEFT) AND SAM PATRICK (RIGHT) (SOUNDBITE) (English) SAM PATRICK, PHD STUDENT AT UNIVERSITY OF NOTTINGHAM, SAYING: "We've basically got a giant tank, we've got 2,000 litres of water down here in the bottom. And we pump it up at the back using these powerful pumps, it comes in from one side so what it starts to do is spiral round. And then there's a hole in the centre, so it drains outwards. So doing this we simulate a rotating black hole." DYE BEING POURED INTO WATER BATH CLOSE OF 'BLACK HOLE' AS DYE SPIRALS DOWN VIEW THROUGH SIDE GLASS SHOWING THE SPIRALLING VORTEX (SOUNDBITE) (English) SAM PATRICK, PHD STUDENT AT UNIVERSITY OF NOTTINGHAM, SAYING: "If the water is flowing faster out of the tank than the waves can travel and this is exactly when we get the analogue of of our event horizon. And because we've got an analogue event horizon in our system this will give rise to the same kind of effects that you can observe around black holes. So by creating this experimental set-up here, we are able to study the same kind of effects that occur around black holes without having to travel to the centre of the galaxy and do experiments on them." WIDE OF WATER BATH / DYE BEING ADDED (SOUNDBITE) (English) SAM PATRICK, PHD STUDENT AT UNIVERSITY OF NOTTINGHAM, SAYING: "The key thing about a black hole is that it's got an event horizon. And this event horizon gives rise to some really interesting effects. From the point of view of the water; we can also have an analogue event horizon as seen by the surface waves. So although we don't have a black hole, the surface waves behave as if there were a black hole in the system. That's enough to give rise to these interesting effects and we can then study these effects. So although we don't have a black hole, we still get the same effects that occur around black holes." (SOUNDBITE) (English) THEO TORRES, PHD STUDENT AT UNIVERSITY OF NOTTINGHAM, SAYING: "We have a pattern in the middle; a projector in the middle that projects a pattern on the water. And then we have two cameras on the side that collect [record] this pattern. And by looking at this object from two different angles, exactly like our eyes, we can see in three dimensions." WIDE OF WATER BATH WITH ROBOTIC ARM APPLYING DISTURBANCES TO THE SURFACE WIDE OF WATER BATH WITH RESEARCHERS IN BACKGROUND CLOSE OF RESEARCHERS RESEARCHERS LOOKING AT COMPUTER SCREEN CLOSE OF PATRICK LOOKING AT SCREEN
- Embargoed: 4th September 2017 09:51
- Keywords: black hole super-radiance University of Nottingham quantum gravity
- Location: NOTTINGHAM, ENGLAND, UK / ANIMATION
- City: NOTTINGHAM, ENGLAND, UK / ANIMATION
- Country: United Kingdom
- Topics: Science
- Reuters ID: LVA0016V3MT7F
- Aspect Ratio: 16:9
- Story Text: Scientists are unlocking the mysteries of black holes... in a giant bathtub at the University of Nottingham. A team from the Quantum Gravity Laboratory says they have successfully simulated the conditions around black holes and published the first statistical evidence of an effect known as super-radiance, whereby a wave hitting a rotating black hole can extract energy from it.
They built a specially designed 3 metre by 1.5 metre tub with a hole in the centre. Two thousand litres of water is pumped in a closed circuit to establish a spiralling draining flow, just like in a normal bathtub when the plug is removed. Small waves were then generated at varied frequencies to simulate the enigmatic ripples in space.
"Although we don't have a black hole, the surface waves behave as if there were a black hole in the system," explained researcher Sam Patrick. "That's enough to give rise to these interesting effects and we can then study these effects. So although we don't have a black hole we still get the same effects that occur around black holes."
Black holes are regions so dense with matter that the pulling force of gravity is so strong that not even photons of light can escape their gravitational pull. A black hole's gravitational point of no return is known as the event horizon. Studying them has largely been confined to the realm of theoretical physics.
Led by Dr. Silke Weinfurtner from the School of Mathematical Sciences, their primary experiment is based on the super-radiance theory: that any waves that enter the area just outside - but don't pass - the event horizon will be dragged round by the rotation and emerge the other side with more energy. In effect, extracting energy from the black hole and thus diminishing the black hole's pull.
Once the super-radiant scattering effect is created, a specially designed 3D air fluid interface sensor captures the data.
"A projector in the middle projects a pattern on the water. And then we have two cameras on the side that record this pattern," said researcher Theo Torres. "And by looking at this object from two different angles, exactly like our eyes, we can see in three dimensions."
Torres added that they observed how the wave pattern changed once it had passed the 'black hole' vortex in their system. "Basically it says that something happened. And then by analysing more carefully this scattering pattern we can see if the wave has extracted some energy from the vortex. So, basically the idea is that the wave after the vortex has more energy than the wave before," said Torres.
The team says this 'super-radiance' phenomenon has never been observed before.
"We showed that super-radiance does exist in our vortex flow. This was quite a big result for us because super-radiance is an effect that's been known about since around the 1970s but no one had ever actually demonstrated that it exists in these rotational systems from an experimental point of view," added Patrick.
The research, published in the journal Nature Physics, could lead to similar experiments that demonstrate black hole theories in a laboratory setting that had previously only been hypothesised. - Copyright Holder: FILE REUTERS (CAN SELL)
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