The implications of finding a Dyson sphere

By George Thomas

Many people will have recently heard of the potential discovery of an artefact of alien intelligence around the star KIC 8462852 (If you haven’t, read here for more info http://www.iflscience.com/have-we-really-discovered-huge-alien-megastructure-around-star). Further recent study of the star has ruled this out as an option, but it was an interesting idea. With that said, I want to talk about the potential implications of intelligent, highly advanced, alien life existing in our Galaxy.

 

The object that had been speculated as a potential sign of an advanced civilisation is called a ‘Dyson sphere’. Put simply, the idea is that you surround a star in a dome of solar panels to absorb the light energy emitted, to provide enough fuel to sustain your highly advanced alien race. However, surrounding the entire star in a dome isn’t very practical, for multiple reasons, but lots of spaced out satellites could work as a good alternative source for harnessing power. This concept is known as a ‘Dyson bubble’. The presence of a structure like this around KIC 8462852 would have explained the initial observations, but other explanations such as lots of comets are far more likely.

Illustration of a Dyson Bubble
Credit: Wikipedia

 A lot of news outlets had spoken about us potentially finding alien life, but what if there were aliens; would they have found us? Of course, we haven’t got a giant structure surrounding the Sun to give ourselves away, but one way we have been giving ourselves away is in how, at least for the last 100 years, we’ve been broadcasting radio waves across the Galaxy. Unfortunately the radio waves will have become so spread out in their travel that our signal will be indistinguishable from background noise beyond a few lightyears away. Also, in the case of KIC 8462852, the star is too far away (about 1500 lightyears) for our radio waves to have travelled to any potential life stationed there. Unless the species had spread out to stars much closer to our Sun, they wouldn’t have had time to pick up any signs of technology that we may be giving off.

 

There is, however, the Earth itself, which has been harbouring life for the last few billion years. Any intelligent beings looking out at the Galaxy with the technology to detect our pale blue dot will have been able to tell that we’re sitting very comfortably in the habitable zone around the Sun. This is especially true of any species capable of building a Dyson bubble, which begs the question: if there is an advanced civilisation relatively nearby, why haven’t they come to us?

 

The answer, much to the dismay of sci-fi fans, is probably the restrictions of travel through space. Although there are various theories about using wormholes to avoid technically travelling from one point to another at speeds faster than light, the entirety of physics thus far points to a constant restriction: information cannot travel faster than the speed of light.

 

This isn’t definitely the reason, though. An optimistic view could be that life is so overly abundant in the universe that no alien species has bothered to come to us yet. But, as said, this is very optimistic, and the inability to travel to our stellar neighbours in a time considered reasonable compared to the human life span is a far more likely reason. If they have found us, and can reach us, then they’re making an active choice not to engage with us, which would be a curious decision in itself.

This means that although we may in future discover advanced civilisations dotted around our 

galaxy, we may never be able to reach them. We may not be alone in the Universe, but we 

may well be too far away to ever see our neighbours.

Earth's Larger Cousin

By David Morris 

In March last year, following three years of data accumulation and analysis, NASA disclosed the discovery of an exoplanet (a planet from outside our solar system) that shares enough characteristics with the Earth that it could potentially harbour life, Kepler-186f. Discovered by the Kepler space observatory, the body has a volume of approximately 1.48 x 10²¹ m³, just about 10% larger than Earth. Interestingly, the exoplanet is believed to show very little obliquity, the degree to which the axis of rotation of a mass tilts away from its plane of orbit. This means that it experiences minimal differences in seasonal weather. It is of comparable age to the Earth, is located roughly 490 light years away and can be found in the constellation Cygnus.

Kepler-186f is the first planet outside of our solar system discovered to have both a comparable size to the Earth and to be within the ‘habitable zone’ of its parent star. The habitable zone of a star is the range of distances from it where, given sufficient atmospheric pressure, any present water will be a liquid: a characteristic that is absolutely vital for the existence of life. Many exoplanets have this characteristic, but they are all at least 40 % larger than Earth, making them too dense to sustain life. This is the case for the other four exoplanets that Kepler-186f shares its solar system with. Their large masses draw them closer to their parent star due to gravity, making them too hot and therefore uninhabitable.

Kepler-186f orbits Kepler-186, a star half the size of our Sun. This star is known as a red dwarf, a star cooler and smaller than that of the Sun. Kepler-186f receives roughly a third of the heat energy that Earth receives, making it much less able to support life. The masses of red dwarves are generally so small that orbiting planets are likely to go into tidal locking. This process is caused by the gravitational pull of a mass on an orbiting body, compelling it to rotate at roughly the same rate as it orbits. This means that the same hemisphere is always facing the mass, as is the case for Pluto and one of its moons, Charon. This effect is also employed in getting artificial satellites to orbit the Earth correctly. Tidal locking would cause one side of the planet to be in constant ‘night-mode’ and the other in constant ‘daylight’, resulting in enormous temperature variations and therefore varying phases of atmospheric substances like water. Without a mechanism for swift planetary heat distribution, such as oceans, the planet would be uninhabitable. There is an approximately 50 % chance that Kepler-186f is orbiting its parent star with partial tidal locking. As a result of this, a single rotation of the exoplanet about its axis could take up to weeks or months, contributing to the prevalence of the aforementioned planetary temperature differences.

There are a wide range of atmospheric densities and temperatures that the exoplanet could support depending on its chemical composition. The greenhouse gases that keep a planet hot could be present in any number of concentrations, maintaining a specific surface temperature. The age of the red dwarf is also important as it will emit differing amounts of various types of radiation depending on its age. For example, if the red dwarf emits high levels of high-energy, ultraviolet radiation, as is prevalent in young red dwarves, the energy supplied could cause lighter elements like hydrogen and helium to escape the gravitational pull of the exoplanet, removing mass from its surface.

Given the information NASA has gathered, it is possible that Kepler-186f could support life. However, in order to fully determine its capabilities, the surface composition of the exoplanet needs to be examined further. Exoplanetary surface composition is very difficult information to obtain, especially for a body so far away. This is one of the many tasks that NASA is constructing the James Webb Space Telescope for, due to launch in October 2018. The telescope has been under construction since the beginning of 2011 and is planned to be sent to the L2 Lagrange point, 1.5 million kilometres from Earth, the furthest from the Earth that any man-made device has ever been sent. Consequently, the question as to whether other life outside our solar system exists may be answered within the coming years.

@Bristol Space Odyssey

by Laura Rogers

Ever wanted to play on all the exciting exhibits at the At-Bristol science centre, but felt too embarrassed as they are surrounded by children? Ever wanted to stargaze on the roof overlooking Millenium Square? Ever wanted to drink alcohol whilst at a museum? Well, adult-only nights at the At-Bristol are the perfect excuse.

I was lucky enough to attend ‘A Space Odyssey’, the adult-only night that enabled you to adventure into the depths of the sky and discover how we explore them. The night was from 6:30 to 10:00pm, however, this was not enough time to explore the whole venue and experience everything they had to offer. An insightful talk was given, in which experiments were conducted to show how satellites work. A personal favourite was when a spring was placed in hot water and immediately straightened. This phenomenon was applied to a model of a satellite, enabling it to open its wings via a current being passed through the wire, heating it up and straightening it. The welcoming Bristol Astronomical Society exhibited their telescopes, allowing us to observe stars in the sky. It was fascinating to see how a tiny spec in the sky was actually 2 stars, one orange and one blue. We had the chance to explore a recreated Martian landscape and analyse rock samples which was incredible.

At-Bristol has hundreds of interactive exhibits including: a giant hamster wheel, a walk in tornado, various water activities, exhibits to learn about the human body and many more. They were great fun to play with and helped to develop my scientific curiosity. We aimed to play with as many interactive exhibits as possible; my favourite was ‘startle’. This involved air suddenly spraying into your face, the reactions were recorded and played back in hilarious slow motion.

One of the latest exhibits, in the Zone, gives information on the science behind being a top athlete. It involves completing 5 challenges where you are set against an opponent. It was enjoyable and exciting, however, the only challenge I won was the final sprint finish! 

If you have seen the strange silver ball in Millennium Square, you may or may not know it is in fact a planetarium. You can take my word that it is much larger inside than it appears outside (Bristol’s Tardis) with a majestic screen spreading over the top of the sphere. We were transported from a view of the sky affected by light pollution to an astonishing view of the sky from a nearby countryside area. Just by listening to the audience’s ‘ooo’ and ‘ahh’ it was clear that everyone found the view spectacular. The autumn constellations were shown and a fantastic Astronomer, Lee, described the constellations and their associated Greek myths. This experience was breath-taking and is something I would highly recommend. I even recognised some constellation patterns and can now show off as I know the names and stories. 

The adult-only nights are great fun and enable you to experience the thrills of science through interactive exhibits, talks and demonstrations. The next adult only night is on Monday 9th December so keep an eye out for it.

Earth’s close call

Owen Gethings

As far as close shaves go, this Friday the 15^th the Earth will be sailing pretty close to the wind. The small Near Earth asteroid, 2012 DA14 is currently hurtling towards us at 25,791mph (or 11.53km/second) and will pass Earth at a distance of 17,200 miles. That doesn’t seem very close but let me put that into perspective. The asteroid will pass within the ring of geosynchronous communication and weather satellites currently orbiting at 22,200 miles above the equator. Although NASA’s NEO program, that currently monitors around 9697 Near Earth Objects, with 961 of these being larger than 1km, say the asteroid will not hit us, it does give researchers an opportunity to study the large object. The asteroid will be visible through binoculars, albeit a very faint spec of light crossing the sky. The asteroid will be visible in the constellation leo, travelling towards the plough at around 7:30pm UK time.

The trajectory of DA14

Your journey

Did you know that by just sitting at your computer all day in your room you will travel ~40,075km?

Ignorance is Bliss: Sound Barrier Damaged Beyond Repair as Thrill-Seeker Goes Supersonic

Ryan Hamnett

In what is believed to be the first case of its kind, Austrian daredevil Felix Baumgartner has been charged with extravehicular speeding after jumping from the edge of space, sources confirmed last Sunday. Extravehicular speeding, or, speeding without the use of a motorised vehicle, is an offence previously reserved for comic books, Jamaican sprinters, and Lance Armstrong going downhill at peak “fitness”. Therefore, it was believed that the judge would be lenient with his sentencing, given the obscure nature of the crime. However, the thrill-seeking skydiver, who was unlucky to be caught by an orbiting meteorological satellite, was able to deal some considerable damage on the joyride, breaking the sound barrier which he claims he “didn’t even see” as he smashed through it at 834 mph, or Mach 1.24.

"Baumgartner's new Facebook profile picture, with an estimated 3 likes"

In a strange echo of a previous highest dive, achieved by Chelsea striker Adrian Mutu in 2004, the case took a turn for the worse for Baumgartner when a blood test revealed dangerous amounts of stimulants in his body at the time of the jump, primarily caffeine. When reached for a comment, Baumgartner claimed “I was under the impression it would give me wings.”Clearly he did not realise that the limited atmosphere at his height would render wings useless.


Although falling from a height of 128,100 feet, 39,400 metres, 24.2 miles, or “a bit further than Paula Radcliff can generally run” may seem impressive, many have questioned the skill actually required. NASA, currently believed to be at the forefront of balloon technology, are apparently delighted with the result of sending a man into space and actually returning. However, sources close to the balloon itself suggest it is not happy with the lack of limelight it is receiving: “Any idiot can fall. I’d like to have seen him get up there without me.” Diver and British sportsman Tom Daley has criticized Baumgartner as well. “While the sheer height and number of flips were impressive, he wouldn't have got many points for technique or water entrance, although admittedly there was no splash,” added the bronze medallist.

Members of the public have also stated their lack of awe at the stunt. “I once dived off the high board at Riverside,” said one American, speaking of his local pool. “And I didn't even need all that safety equipment.” Upon seeing the fall, some seemingly uni-ocular members of the public asked “Is it a bird? Is it a plane?”, evidently having no clear sense of depth perception. Meanwhile, Rangers FC are apparently annoyed that their recent free-fall record was broken so soon, having fallen four tiers in the Scottish Football League in the summer of 2012.

                Is it too late to change my mind?

The Diamond Planet

Hannah Bruce Macdonald

While it may sound like it’s drawn from science-fiction, scientists have shown that the imaginatively named planet, 55 Cancri e, may consist of up to a third diamond. Initially, when first discovered in 2004, it was considered to be Earth-like and it was believed that the surface of 55 Cancri e was covered with supercritical fluids (a gas with fluid properties at high-pressure) flowing from its rocks. However, further calculations on its density have allowed scientists at Yale University to establish that the planet is mainly carbon-based. This carbon is present in both diamond and graphite forms, with the other constituents of this rocky planet including silicates, silicon carbides and iron.

   

This extra-solar planet, orbiting the sun-like star 55 Cancri A, has a diameter around twice that of the Earth and its mass is 7.8 times larger. A third of this planet is made of diamond, which is equal to 2.5 times the mass of our Earth. Our relatively carbon redundant Earth only mines 26,000 kg annually! 

While it sounds like an ideal source of wedding ring stones, and mining may seem like a promising venture, this ‘Super-Earth’ is 40 light years away; a distance of 8,968,390,660,000 marathons, within the constellation of Cancer. Its ‘year’ lasts only 18 hours and it is so close to its star, that it can reach 2,1000 Celsius! To add to the impossible heat there is predicted to be little water and that any life would be unsustainable in this environment. So if you’re after your own Star of Africa, you will probably have more luck stealing the crown jewels than reaching this diamond in the sky.

Check out this video:

Reach for the stars

NASA astronaut and flight engineer Sunita Williams appears to touch the Sun in this amazing photograph snapped from space. It was taken during the 32nd expedition to the International Space Station after an epic 6 hour spacewalk on September 5th 2012. The astronauts had been making routine repairs and installing a Main Bus Switching Unit (MBSU). Earlier this week two astronauts at the international space station were forced to make repairs with a $3 toothbrush, they saved around $100 billion of damage. The Space Station is currently home to six astronauts: Sunita Williams and Joe Acaba of NASA, Aki Hoshide of the Japan Aerospace Exploration Agency, and Russian cosmonauts Gennady Padalka, Yuri Malenchenko and Sergei Revin.

Curiosity lands on Mars

Glorious gas giant

Tom Stubbs

This spectacular photo shows Saturn’s legendary rings and two of its moons. The photo was snapped by NASA's Cassini spacecraft as it orbited the gas giant. It allows scientists to get up-close and examine the shifting motions and intricacies of Saturn's rings. The Cassini spacecraft arrived at Saturn in 2004, it recently changed orbit gaining this new perspective. Saturn is currently shining bright in the night sky so see if you can spot it.

For more information on the Cassini mission:

NASA - http://saturn.jpl.nasa.gov/photos/