Black Holes and Gravitational Waves

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Alexander Marks

On the 14th August 2017, the fourth set of gravitational waves were detected. Although the first waves were recorded in early 2016 by LIGO (Laser Interferometer Gravitational-Wave Observation), this time three different observatories detected the gravitational waves. A pair of black holes caused these waves by violently merging together.

Three Scientists at LIGO, Rainer Weiss, Kip Thorne, and Dr Barry Barish have just been awarded the Noble Prize in Physics, for the first detection of gravitational waves and it was these three scientists who designed and ran the two LIGO observatories, situated in Washington and in Louisiana. In the most recent detections a new observatory in Italy called Virgo also measured the same waves.

Why are three detection’s better than two? Three detection’s allow scientists to better pin point the origins of the signals, 20 times more precisely than just two. This is key for follow up observations. It also provides more information about the object that made them, such as the angle they are tilted at compared to Earth.

Gravitational waves where first predicted by Einstein’s theory of relativity back in 1916. This theory was ground breaking and combines space and time to form the space-time continuum. His theory states that any object with mass warps the space-time continuum, the more massive the object the bigger the warp. It is these warps in space-time that cause gravity.

The famous equation of general relativity is incredibly hard to solve, and requires super computers to find solutions. One of the solutions predicts gravitational waves.

Gravitational waves are caused by all objects as they move through the space-time continuum.  Every object makes gravitational waves, meaning that even a tiny snail moving in the grass produces them. They ripple through space-time much like ripples caused by throwing stone in a still pond.  Gravitational waves were the last part of Einstein’s theory to be proven.

The equation predicts that gravitational waves would travel at the speed of light and carry information of the objects causing them. But most of the gravitational waves are too weak to be measured. It requires a massive object to create the large enough ripples in space time to be measured.

Enter black holes and neutron stars. Black holes are the most massive objects in the known universe. Their mass is so large that light cannot escape their gravity. When two black holes orbit very quickly around each other and eventually merge, they create immense distortions in the space-time that can be measured on Earth.

By measuring the gravitational waves and using Einstein’s theory of relativity, scientist can learn a lot about the darkest parts of our universe. Scientists can predict the mass, rotation and how powerful the event was.

Neutron stars are the remains of stars that have collapsed in on themselves, and are also very massive and could theoretically be detected as well. Yet, there has been no detection of gravitational waves caused by them but, there is promise that these will soon be detected as well.

Even the largest ripples in space time are very difficult to measure. LIGO and Virgo are carefully designed to detect these ripples. Each of the observatories is shaped like an L. Each arm of the L is a long tunnel that are vacuum sealed. At the end of each tunnel there is a mirror, and a split mirror where the two meet. (A split mirror can split laser light in two, and send it in different directions).

Lasers are sent down the tunnels at the same time, without the presence of gravitational waves both lasers would return at the same time. When gravitational waves are present the space-time is warped in such a way that one mirror gets closer and the other gets further away. This results in the laser beams returning at different times, allowing scientists to measure the amount the mirrors were warped. This measurement is very small, about 1000 times smaller than a proton.

This means the bigger the gravitational waves the larger the time gap between the lasers returning. As the time gaps are so small, only very massive object can produce waves big enough to be detected.

 

The black holes that created the most recently detected gravitational waves had masses of 25 and 31 times the mass of our sun. They were orbiting each other 1.8 billion light years away and merged into a black hole of 53 times the mass of our sun. This is a supermassive black hole, and is bigger than ever expect to be found.

 

This is the third black hole to be bigger than expected. Black holes of this size appear be more common than originally thought and the rate at which they occur will soon be figured out.

 

The observatories are currently being upgraded and will become even more sensitive. Scientist hope that when they are turned back on in Autumn 2018 they will detect up to ten of these events each year. There is also hope of detecting gravitational waves from neutron stars as well.

 

With observatories planned in Japan and India, it can be expected to find new phenomena occurring in the universe that may have been thought impossible.

Aliens! Hoaxes and conspiracy theories.

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Sophia Akiva

“10 unbelievable real alien encounters!” is not an uncommonly used click-bait topic, attracting the curious and the gullible to questionable advertising sites. Our fascination with the possibility of mysterious extra-terrestrial beings has made us vulnerable to con artists, made us question our governments and worst of all, has even lead Ancient Aliens to take over a formally reputable TV channel. But is there any truth to these stories or are broadcasting stations merely exploiting footage (of conveniently poor quality) in the name of profit?

To begin with, let me honour one the greatest alien conspiracy theories to date, one that kept the world on the edge of its seat long after the initial event. Even now, the Roswell incident continues to serve as inspiration to the media, referenced heavily by believers and critics alike. On many occasions it had been named the most iconic instance of extra-terrestrial encounters yet equally frequently called the most thoroughly debunked hoax. The supposed weather balloon crash occurred in 1947 and was addressed by the Roswell Army Air Field personnel during a press conference, leaving no room for doubts or excitement so the story quickly and quietly faded away. It remained dormant for three decades, when it was awoken by the popularised hobby of spreading conspiracy theories. The believers so adamantly pursued circumstantial evidence and foggy memories from thirty years before that stories began to evolve and grow, fuelling the public’s interest with their concocted details and flexible accounts. Several books were published on the topic of Roswell, some exploring these fabricated tales through an imitation of the scientific method and some who concluded that the evidence presented was simply insufficient and often gathered from unreliable sources. The pressure on the Air Force to declassify the information from 1947 continued to mount until in 1994 they revealed the truth; that a weather balloon was a high-altitude military surveillance balloon used to monitor for evidence of nuclear testing as part of Project Mogul[1].

There have been multiple alien autopsy videos released to the public with evidently varying production budgets despite the increasing availability of special effects software. These videos, that have once entranced nations, have now taken the place of viral jokes, shared between school children and bored office workers. So, what has made us lose our faith? Have we become desensitised to the excitement of possibility or have we at last learned to question what we see before us? It is true that alien autopsies have never been supported by physical evidence and in many instances the creators themselves have stepped forward with confessions of their deceit. Perhaps this crucial data is being withheld by global intelligence agents, hidden away in coded X-files that take such extensive funding to maintain as to leave the less valuable military and economic information vulnerable to hackers and leaks.

Another famous, but very short lived, alien hoax was the accidental country-wide panic caused by the broadcast of The War of The Worlds on Halloween of 1938. Orson Welles and the Mercury Theatre team created a sensational contemporary adaptation of H.G. Wells’ novel that was done a little too well. Initially, the team had little hope of success with this project and had it not been for some major last-minute rewriting, the show would have been nothing more than a pleasant hour for some few dedicated fans. However, due to problems with scheduling, the show was unintentionally timed more as a genuine news broadcast. This, combined with the brilliant efforts of the actors and sound technicians quickly caused widespread fear among the listeners who tuned in too late to hear the introduction explaining the adaptation of the 19th century novel. It is generally believed that the chaos caused by the realistic reports of Martians rapidly invading the Earth was unintended but as with many alien hoaxes, it sure worked in favour of the creators’ careers.

To say that all current evidence for visitations from extra-terrestrial beings is comprised of hoaxes and conspiracy theories does mean that there is no hope of intelligent civilisations sharing this universe with us. We have reached out with the Voyager golden record that contains images and sounds from Earth as well as diagrams and equations expressing our current understanding of mathematics and laws of physics. Unfortunately, it will be far in the distant future that an alien race may receive this little guide to life on Earth. For decades now, we have been listening out for a message from beyond. One promising sign came in 1977, when a researcher at Ohio State observatory was so amazed by a strong radio transmission that he wrote “Wow!” in the margin, coining the instance as the Wow! Signal. The possibility of this being evidence of alien communication has lingered on the minds of astronomers for decades, but in all this time we have not heard from them again. The frequency of this transmission corresponds to hydrogen, so although it was highly unusual, it can possibly be explained by continued development of our astronomical understanding. Be it intelligent aliens or physics that we have not yet discovered, the truth is, and will always be, out there.

[1] http://muller.lbl.gov/teaching/physics10/Roswell/USMogulReport.html

One ticket for the Enterprise please! Has China successfully created an sustainable EM Drive?

 

320x240Shannon Greaves

Space is awesome. So awesome that it has had the global powers stuck in a space race even before America took that one giant leap for mankind. Everyone is eager to explore new planets, solar systems and travel faster than light (FTL) with their very own warp drive Enterprise. Well to all us astronauts at heart, that day may be coming sooner than later, now that China has released a video claiming not only to have a working EM drive, but also are claiming to have one already in space on their space laboratory ‘Tiangong-2’! Prior to this news of success from China, China was reported to have only been studying the EM drive, with no reports of successful functionality. Furthermore, both the UK and NASA have also been working on creating an EM drive, with a mixture of breakthroughs and problems. But before we get into the thick of things, let us have a quick review on some important information about the EM Drive.

The Electromagnetic drive (EM Drive), scientifically known as a radio frequency resonant cavity thruster, makes use of microwaves and particles that are bounced around inside an asymmetrical-shaped cavity, which produces thrust with an increasing momentum. Much like to if you were in a box, pushed on the side, and started to move with acceleration. What this means simply is that an EM drive creates thrust without the need for a propellant. Sadly, what an EM Drive isn’t is a warp drive as seen in Star Trek. Unlike how the EM Drive creates thrust, a warp drive appears to enable FTL travel through warping the fabric of space and time around a ship, allowing it to travel less distance.

Still, a working EM Drive would mean a whole bunch of good things for us, including a much faster way of travelling through space (just maybe not FTL Level). A fully functional EM drive would mean there would be no need for heavy propellants such as rocket fuel on board, and would result in a trip to mars only taking between 70-72 days, compared to the average of 270 days it takes us today. What’s even more impressive, is that according to NASA, with an EM drive it would only take us 92 years to travel to our nearest solar system! In addition to faster space travel, the EM drive would result in: cheaper space travel, solar power stations with cheap solar-harvesting satellites that could beam power back to earth, and generally provide us with a greener and convenient energy source for travel.

So, what are we waiting for!? Well before you go buy your space suits and tickets to China, there is a lot of discussion on whether China’s claims and experiments with the EM Drive are true. So far, all China has given us is a press conference announcement and a government sponsored Chinese newspaper (and China doesn’t have the best record of accomplishment for trustworthy research). Within the press conference they also claimed to need to do further experiments to try to increase the amount of thrust being produced. What we need is a peer-reviewed paper, which would not only provide conclusive evidence for their results with the EM Drive, but also confirm the reliability of their claims to testing it in space. China does have some stability to their claims however, with China claiming to have produced similar results to that of the work of NASA’s EM Drive experiments. NASA’s has been working equally as hard on the EM Drive, and have produced several models of EM Drives producing Thrust. They even finally managed to publish a peer review paper, with an EM Drive producing small amounts of Thrust within a vacuum. This gives a little backup to China’s claim of an EM Drive in space.

The biggest problem the EM Drive faces is that arguably its biggest contribution to science today is also its biggest problem and why many experts contest against it. The very physics of the EM Drive not requiring a propellant violates Newton’s third Law of Motion, “for every action there is an equal and opposite re-action”. So, on the one hand, where this would mean that the EM Drive would change the basis of how we understand physics, it also means that no one can explain how it works. Without this explanation, the consensus is that we can’t possibly use and sustain the EM Drive.

So, what happens now? Well we are going to have to wait to see if China releases that peer review paper, but even without that we have made a lot of development in our goal to space travel. The combined effort of China, NASA and other national institutions have brought the EM drive closer out of the theoretical, and into the possible. There has even been some theories created to explain how the EM Drive works, “quantised inertia” being responsible for creating this thrust. If true, this would mean that the EM Drive would not completely violate the conservation of motion, but adapt it. If you’re interested in the applications of “quantised inertia” to the EM Drive, then consider the works of Dr Mike McCullock. Furthermore, for those of you wanting that FTL warp drive, then there is some hope! NASA engineers have been reporting on forums that when they fired lasers into the EM Drive’s resonance chamber. The result was that some of the beams traveled faster than the speed of light. This suggests that the EM Drive may have the capacity to produce the needed “warp bubbles” for a warp drive! Nasa has even been designing a warp drive ship if you want to check that out to! Now, I’m off to watch some Star Trek, but keep an out for the announcement of a reality tv version!

Sally Ride’s Space Legacy

220px-sally_ride2c_america27s_first_woman_astronaut_communitcates_with_ground_controllers_from_the_flight_deck_-_nara_-_541940Jonathan James

Sally Ride was an American physicist and astronaut, most famous for being the first American woman in space, in 1983, and the third woman in space behind Russian Cosmonauts Valentina Tereshkova and Svetlana Sativskaya. As well as being the youngest American to have travelled to space, at just 32, she is less well known for being the first known LGBT astronaut, a fact not revealed until after her death in 2012. Whilst having been married to fellow astronaut Steve Hawley from 1982 – 1987, her partner for the next 27 years would be Tam O’Shaughnessy, who she met when both were aspiring tennis players years earlier.

Ride joined NASA in 1978, having answered an advertisement in a newspaper for people to join the space programme. Prior to her first flight in 1983, she worked as a communicator for the second and third space shuttle flights and worked to develop the ‘Canadarm’ robot arm, used by space shuttles to deploy and recover deliveries. The flight in 1983 subjected her to a lot of media attention, mostly because of her gender. During one press conference, she was asked a series of extremely sexist question by the media, including whether she would cry if things went wrong, and whether the flight would damage her reproductive organs. Despite everything, Ride simply insisted she was an astronaut.

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The Challenger shuttle, moments before the horrific disaster.

On June 18, 1983, Ride because the first American woman in space as a crew member on the space shuttle Challenger. The crew deployed two communication satellites and carried out many drug experiments in space. Ride was the first woman to use a robotic arm in space. A year later, in 1984, Ride embarked on her second mission on the Challenger (sadly to be her last, following the Challenger disaster of 1986, which took place months before she was due to go to space again for a third time.) In total, Ride spent over two weeks in space.

Following the Challenger disaster, Ride moved from space flight to the political sphere, working on the Rogers Commission to investigate the reasons behind the disaster. Later, she would go on to found NASA’s Office of Exploration, which continues to lay the groundwork for much of NASA’s future exploration. She would also work with schools to encourage students to pursue careers in the space industry, contributing to seven short stories aimed at children, and spent some time as a professor of physics at the University of California, San Diego.

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Then US President Barack Obama, awarding Sally Rides posthumous Presidential Medal of Freedom to her partner, Tam O’Shaughnessy.

Sally Ride’s legacy continues to this day – she has received several accolades both during her lifetime and posthumously. In 2013, she was awarded the Presidential Medal of Freedom by then President Barack Obama. A year later, in 2014, she was induced into the Legacy Walk, an outdoor public display that celebrates LGBT history and people.