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.


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.


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.

Are Aliens Out to Get Us?

Jonathan Cooke

For a species that is so often looking up to the stars thinking ‘are we alone?’, we tend to populate our fictional universes with less than benevolent compatriot species. Look at some of the more popular science fiction movies and stories to be released in the last century. War of the Worlds, Alien and even the recently released Life all approach the question of extraterrestrial life the same way: it’s out there, and it’s out to get us.

Since it is such a speculative field, there is virtually no consensus on how we might react upon first contact, simply because we don’t know what sort of aliens will turn up. The developing view is that, if there is other life in the universe it’s likely to be microbial in nature. If there is anything that the much-lauded tardigrades have taught us, it is that microbial life will find a way to survive. Therefore, most space-based programs are focused on the detection of this so called primitive life (Is it fair to call it primitive when they can do some pretty amazing things?).

Most missions have focussed on our closest sister, Mars, and its dry riverbeds that provide some tantalising bits of evidence that all might not be dead on the red planet. Methane is unusually high in the Martian atmosphere. As a gas that is highly reactive and therefore tends to disappear without regular top ups, this is indicative that something is replenishing it. Methane in our own atmosphere is typically produced from biotic sources; meaning that, from our experience, traces of methane might be indicative of life.

Of course, alternative theories exist for the presence of methane, including geological sources of the gas. But what if our rovers were to discover bacteria living on the surface of the red planet? What would we do with it? Well it wouldn’t be coming to our planet anytime soon –  none of the rovers currently on the planet are equipped for that sort of mission. Even then, the samples would have to be tested and tested again to ensure that they aren’t just contaminants from Earth. They’re unlikely to alive by the time they reach Earth under strict contamination procedures. So, don’t worry, no Martian plague will be giving you the sniffles.

Alien View From The Moon Earth

Image Credit: Max Pixel

Anywhere else we are currently scouting for life would face similar contamination issues. Europa for instance, one of Jupiter’s larger moons, is being targeted as our next life-seeking venture to the stars. With an ocean thought to be buried underneath its permanent ice-sheet casing, many scientists believe that ocean temperatures may just be warm enough to support the development of life, if again, simple in nature.

So that basically covers what’s known; in our solar system –  at least there won’t be any tripods bursting out the ground anytime soon to exterminate us and Tom Cruise! But what about farther afield? Well, many radio telescopes are turned to the farthest reaches of our galaxies; and news publishers love a good story of astronomers finding ‘habitable’ exoplanets. If you pay attention to the Drake equation, there should be 1,000 to 100,000 intelligent civilizations in our galaxy. So why haven’t we heard from our cosmic neighbours.

There are many reasons that we might not have heard from them, and many reasons we should be thankful for that. If we’ve learnt anything from our own behaviour on Earth, the less technologically advanced society rarely survives first contact with a more advanced society. The most glaring example of this is the fate of the Native Americans in the wake of Europeans discovering the New World.

This is the cautionary tale that Stephen Hawking told in 2010 when questioned about our first meeting with E.T. On the other hand, many scientists question the validity of Hawking’s reasoning. As mentioned above, many are more worried about what the aliens bring with them accidentally rather than deliberately. As illustrated in H. G. Wells’ famous novel The War of the Worlds, contact with a previously unencountered pathogen can be devastating to any organism. Whether it was the Mayans and typhoid and influenza, to African swine fever in the American pork industry, foreign pathogens tend to wipe out whole communities before any resistance can develop. Just ask the abandoned Mayan cities of the Amazon.

Of course, other questions arise which are a bit harder to answer. What if the alien civilization is warlike? What if their ethics system is not comparable to ours? What if, and this has been considered, we are the ‘life, but not as we know it’ variety in the universe? Many astrobiologists have postulated that silicon based lifeforms may exist (we are carbon based), so what if we’re just too alien for them to visit?

An even sadder alternative is that we are truly alone, that alien life is non-existent, (considered highly unlikely) or that we are one of the first intelligent civilizations to evolve in the galaxy. Perhaps intelligent life is the exception rather than the rule. The Fermi paradox points to how extremely unlikely our own path to survival was. Maybe many creatures on that road seemly get snuffed out by Natural Selection before that point.

In any case, what keeps many scientists up at night is not thoughts of alien invasions, but thoughts of alien illnesses. Perhaps what we should be preparing for, and indeed looking for, is what makes little green men feel ill.

TRAPPIST-1: Could This Newfound Star System Hold Alien Life?

Josh Bason

On February 20th 2017, NASA announced a press conference to discuss a “discovery beyond our solar system”. Two days later they revealed the TRAPPIST-1 system; a series of seven earth-size planets orbiting a star 39 light years from Earth. The announcement of this discovery and the discussion that followed has circled one tantalising question – could the TRAPPIST-1 star system harbour extraterrestrial life?

The scientists at NASA certainly seem excited about the concept. Their search for exoplanets – that is, planets orbiting stars other than our own sun – had until this point yielded only a handful of potentially habitable worlds. Among TRAPPIST-1’s seven planets, however, no less than three have shown this potential, setting a record for the most known earth-like planets orbiting one star.

These worlds were highlighted by the scientists primarily for their location in the so-called ‘habitable zone’. This describes the range of orbit sizes where, dependent on the size of the planets and the star, it is neither too hot nor too cold for life to sustain life.


Artists impression of the surface of TRAPPIST-1f, the fifth planet in the TRAPPIST-1 system Credit: NASA/JPL-Caltech/R. Hurt, T. Pyle

Further investigations by NASA scientists have also yielded promising results. Using precise measurements of the size and mass of the planets, the researchers were able to calculate estimates for the density of each of TRAPPIST-1’s worlds. These density measurements are key to understanding exoplanets as they give us our first insight into their composition.

Of the seven planets in the newly-discovered system, six have been described as ‘rocky’ – that is, more comparable solid planets like Earth and Mars than gas giants like Jupiter and Saturn. The seventh planet, which has the widest orbit and an undetermined mass, has been provisionally described as ‘snowball-like’.

Despite these hopeful indications, there is also a body of evidence which is significantly less inspiring. Firstly, while it’s tempting to imagine TRAPPIST-1 as a distant copy of our own solar system, the absence of two planets is not where the dissimilarities end. The most striking difference between this newly-discovered system and our own is the star which lies at the centre.

The star is classified as an “ultra-cool dwarf”, meaning it is both ten times smaller than our sun and less than half its temperature. While this doesn’t sound like a recipe for warm earth-like planets, the small size of the star is counteracted by the proximity of the planets which orbit it.


NASA’s illustration of the size of TRAPPIST-1. (Credit: NASA/JPL-Caltech/R. Hurt, T. Pyle)

The seven worlds of the TRAPPIST-1 system all orbit between one and five million miles from their star. This means that all seven planets could fit comfortably in the space between the sun and Mercury, with its 58-million-mile orbital distance. While the size of the TRAPPIST-1 system isn’t necessarily a barrier to the formation of life, it certainly represents a significant divergence from the only solar system where we’ve ever observed it.

It’s also important to bear in mind how little is known about the planets of the TRAPPIST-1 system. Despite the array of concept images released by NASA in the wake of the announcement we don’t, in fact, have any idea what the planets look like. The planets were found, or more accurately their existence was inferred, by observing the light emitted by the star they orbit.

This process, known as transit photometry, involved watching the star’s brightness over time and finding dips in luminescence when planets passed in front of it. From this information, NASA scientists extrapolated a range of information, such as their size, mass and orbital distance. What this technique doesn’t reveal, however, are other key factors that determine the habitability of a planet.

Because of this, we still do not know whether any of the TRAPPIST-1 planets contain atmospheres, which are vital for life, or magnetic fields, which can protect life from deadly solar wind. NASA are also not discounting the possibility that some or all the planets may be ‘tidally locked’, meaning that one side may permanently face the sun with the other half perpetually facing away. Conventional wisdom suggests life would be impossible on such a planet, as one half would be too hot for life and the other too cold. More recent evidence, however, has suggested otherwise.


NASA’s idyllic concept art is based almost entirely on speculation. (Credit: NASA/JPL-Caltech/R. Hurt, T. Pyle)

Furthermore, since the announcement of the NASA’s discovery, two pieces of research have poured cold water on hopes of life in the TRAPPIST-1 system. The first, published on March 30th, detected frequent flares emitted from the system’s star. Considering the small orbital distances of the nearby planets the authors feared that these huge releases of energy may disrupt the atmospheres of the planets and that without the protection of strong magnetic fields, life in the system may be impossible.

If that wasn’t disheartening enough, research published on April 6th revealed a new climate model to assess the habitability of exoplanets. The study concluded that only one of the planets, TRAPPIST-1e, was likely to support liquid water. If this planet does not possess a substantial enough magnetic field to weather the flares from its nearby star (something scientists feel is unlikely), all hope for life in TRAPPIST-1 may be lost.

Despite this disappointing news, research into TRAPPIST-1 continues. NASA has announced plans to use its new James Webb Space Telescope, launching in 2018, to search for key atmospheric components such as oxygen and water in the system.

The increased sensitivity of the Webb telescope will also allow the surface temperature and pressure of the planets to be measured, answering yet more questions about the habitability of the system. Until then, however, the hospitability of the TRAPPIST-1 system remains very much in question.

Feeling Spaced Out: The Body in Orbit

Josh Bason

On November 2nd 2000 the first crew arrived at the fledgling International Space Station. In doing so they began a 16-year human presence in Earth orbit which continues to this day. While this is a massive achievement for humanity, we shouldn’t be fooled into thinking that the many difficulties of long-term human space travel have been overcome. Space is an incredibly hostile environment and has a long list of detrimental effects on the body, ranging from the inconvenient to the potentially deadly.  

This first of effect of space travel is hard to miss. Take a look at the photo on the left showing British astronaut Tim Peake in orbit on the International Space Station (ISS). Then compare it to the photo on the right showing him down on Earth just days earlier. Obviously, his face looks much rounder and more swollen on the left, and this isn’t unusual in astronauts.


Tim Peake on the International Space Station (left) and a few days earlier on Earth (right)

Image Credit: Wikimedia

When a human reaches orbit and feels microgravity (NASA’s technical term for weightlessness) for the first time, the fluids that fill their bodies change their distribution dramatically. These fluids, no longer held down by gravity, rush into the upper body causing facial swelling, bulging veins and congestion of the sinuses.

The effect of this change is like a bad head cold; it’s uncomfortable and messes with the astronaut’s senses of taste and smell. While no one loses sleep over an astronaut temporarily losing their sense of smell, the dulling of taste can provide a challenge to chefs preparing food to be eaten in orbit. To compensate, cooks make space food extra spicy, so astronauts don’t have to suffer bland food for their six month stays on the ISS.

Space sickness (or Space Adaptation Syndrome) is another side-effect of orbital travel that’s hard to ignore – for the astronauts at least. As their vestibular system (the fluids in their inner ear which tell them which way is up) struggles to adjust to a world where ‘up’ and ‘down’ don’t mean much, around 50% of astronauts experience nausea and disorientation.

The symptoms of space sickness don’t last too long though – after a couple of days in orbit the symptoms of space sickness subside as the vestibular system of the space traveller adjusts to its new surroundings. Unfortunately, for many astronauts (including Britain’s own Tim Peake) space sickness returns with a vengeance when they land back on Earth – their vestibular system has adapted to weightlessness so completely that the return of regular gravity is dizzying.

The weightlessness of Earth orbit also has some more serious effects on the human body. When an astronaut spends time in space, they begin to lose huge amounts of mass from their muscles and bones. The reason behind both is simple: use it or lose it.

When standing on Earth our legs and spines are constantly working to keep us upright. With no weight to support in orbit, the body starts to break down these bones, washing their vital calcium content away in the bloodstream. This leads to bone loss of up to 1% for every month spent in space.

Muscle loss in microgravity can be even more dramatic, with up to 20% loss from just one week in orbit – especially from the so-called ‘antigravity muscles’ of the legs and back which keep us upright here on Earth.

Needless to say, this is a huge problem for astronauts. Not only do they need their bones and muscles for strenuous activities in space, studies have shown that while muscle mass recovers relatively quickly back on Earth, bone density never completely returns to normal.

To try to combat this, the ISS is equipped with an artificial gravity treadmill, in which astronauts are pulled onto a running surface by straps. This not only gets their muscles working but puts their bones under compression, encouraging them to retain their precious calcium.


Astronaut Frank De Winne working out on the same artificial gravity treadmill where Tim Peake famously ran the London Marathon in space

Image Credit: Wikimedia

Another substantial problem for space travellers is the impact weightless has on their eyesight. 80% of astronauts are thought to suffer from Visual Impairment Intracranial Pressure syndrome, a condition caused by space travel which does huge damage to the eyes.

Brain scans of returning astronauts show eyes that have been compressed top-to-bottom, pushing the retina backwards into the brain. NASA scientists believe this is caused by the increased pressure in the skull when bodily fluids shift upwards in microgravity. As yet, this worrying syndrome remains unsolved and untreated.

Finally, not all problems in space emerge from the absence of gravity. Also missing in space is the protective layer of atmosphere that surrounds the Earth. Along with providing us air to breathe, our atmosphere also shields us from cosmic rays – dangerous radiation from beyond the solar system that pummels our planet day and night. During cosmic events called solar storms the Sun throws out radiation too, adding to the barrage of incoming rays.

Out in space, astronauts aren’t protected from any of this radiation; despite significant shielding on the walls of the ISS, projections have shown that astronauts living there could reach their lifetime safe limits for exposure in just 18 months. This is bad news for those planning missions to Mars, as even a brief trip to Mars would take over a year.

Scientists must find shielding methods that are both light enough to take to Mars and strong enough to keep astronauts safe, even during solar storms, or risk causing them serious health problems – mainly in the form of cancers – years down the line.

So there’s still a long way to go until long-term interplanetary trips are feasible for the fragile human body; space remains a dangerous and taxing environment for the people who travel there. Nonetheless, scientists across the world are working to change this, and we at pH7 wish them the best of luck.

Asgardia: A Space Nation

Sophia Akiva

On November 12th, 2016, the leader of the first space nation addressed their new citizens.

Perhaps this is how future historians will remember the rise of Asgardia, a pacifist nation located on an orbiting satellite and founded by Russian scientist and businessman Dr Igor Ashurbeiyli. There have already been over half a million applicants from around the world to become ‘Asgardians’ – inhabitants of this new nation. If the number of applicants continues to rise at the present rate, it will not be long before an appeal is filed with the United Nations by Dr Ashurbeiyli to officially recognise Asgardia as a member state.


Image Credit: Wikimedia

The study of space, both deep and close-Earth, is one of the three main goals of this new nation, the other two being expanding humanity’s reach beyond our green world and a new legal platform along with the introduction of ’astropolitics’. The government structure of this soon-to-be formed country was revealed back in October and will be compiled of 12 ministries. 11 of these have already been decided upon; the last will be left open to debate.

The first of three core satellites are set to be launched in 2017, fully equipped and ready to welcome new inhabitants. This project has so far been funded by Dr Ashurbeiyli, with additional capital from crowd sourcing and private investment. These investors will be the first to receive citizenship, together with scientists working in fields of space research, exploration and technology.

However, there are many problems facing an endeavour of this magnitude. The first is the immense cost associated with space exploration. Dr Ashurbeiyli has avoided discussing Asgardia’s budget so far and no solid financial plan has been outlined yet.

The scientific equipment needed to carry out such a study will require a constant source of energy, as will the maintenance of good living conditions for the residents. This is the second major issue facing a space state. Such a problem can be overcome by taking inspiration from the International Space Station, which is powered by 27,000 square feet of solar arrays. These panels are rotated by gimbals towards the Sun and can generate up to 120 kilowatts of power, which is either used by the equipment on board or stored in batteries for future use. Solar energy is ideal for a satellite as it has no by-products, is generously available above the atmosphere, and does not need to be transported from Earth. The solar-arrays themselves can fold up for take-off and expand once the satellite is safely in orbit.

As the population of this space nation grows, there will be an increased demand for food. Earlier this year, a zinnia flower was successfully grown aboard the International Space Station. An accompanying guide to gardening in microgravity was produced, showing our rapidly increasing understanding of what it takes to grow food in space. With such advancements being made, many are confident that citizens of Asgardia will not be without a solid and nutritious supply of food.

But what about other aspects of their health? Physical strength, endurance and a strong constitution are needed to withstand the forces acting on a space shuttle as it’s taking off. In addition, there are many risks associated with living in microgravity for a prolonged length of time. Even with regular exercise, astronauts can experience bone and muscle weakness, disturbances in heart rhythm and problems with both cardiovascular and nervous systems. Above the protective shield of our atmosphere, there is a much greater exposure to radiation which can lead to several health problems, such as cancer. Fortunately, these issues are currently being studied and with further research, these risks could be reduced. In any case, the early settlers of any space nation would have to pass rigorous fitness tests and physical training, much like the astronauts of today.

Despite the numerous problems facing the future residents of outer space, we must not lose heart. The field of space exploration is a growing one, with increasing public interest and a rising flow of investment. Because of this, more and more research can be undertaken and our understanding of the world beyond our own will continue to improve.  We can hope that it will not be long before humanity will walk among the stars.

Non-carbon-based life; are we looking in the right places?

Alys Dunn

Between one and three planets in each planetary system lie within the ‘habitable zone’, so it is hard to imagine the true scale of the area we are searching. What if it turns out we have been searching for the wrong life in this huge area? All life we know of on Earth contains organic molecules based on carbon. Could it be possible that carbon-based life forms are not the only variation of life within the endless boundaries of space? Perhaps our Earth-centric idea of life has skewed our search strategies; we may have missed a whole spectrum of life that we didn’t know existed.


Image Credit: Pixabay

Why Carbon?

Carbon, the fourth most abundant element within the universe, is regarded to be the basis of all life on this planet. The essential building blocks needed for life, including DNA, fats, tissues and proteins, all contain carbon. It also makes up other vastly different materials, such as graphite and diamonds.

So why has life on Earth evolved to use carbon within its cells? For one thing, carbon has a special property; it can form stable chains of atoms that are at an appropriate strength, which can be broken down or reformed by our cellular processes. Carbon can also combine with lots of other atoms in order to form a large variety of structures with lots of different properties.  This variability, stability and manipulability are the main reasons we have evolved on the basis of carbon.


Silicon, like carbon, is found in group 14 of the periodic table, which means they share the same type of chemical properties. These properties are dependent on the fact they both can form four bonds with other atoms. These similarities make silicon a good contender for a non-carbon basis for life.

Silicon is able to make building blocks appropriate for life that are very similar to those made by carbon. It has even been suggested they would be more stable in more extreme environments, like those found on other planets. For example, silicon based sugars are soluble in liquid nitrogen, which is only liquid below -195.8oC. Nitrogen ‘glaciers’ forming liquid nitrogen lakes and rivers may have been found on the surface of Pluto by NASAs spacecraft New Horizons. However, silicon is more unstable and forms a smaller variety of bonds in comparison to carbon, and so may be less versatile when it comes to the complexity of forming life.


Boron has also been suggested as an alternative to carbon. The properties of boron mean that, like silicon, it is able to form similar building blocks to those made by carbon. It would also be incredibly stable in environments containing ammonia instead of water. However, the relative scarcity of boron compared to carbon in the universe makes it an unlikely candidate for non-carbon based life.


Inorganic chemical cells (iCHELLs) are an invention by Professor Lee Cronin at the University of Glasgow. These cells are made from lots of metals but no carbon. Cronin claims that these iCHELLs have selective outer membranes, compartments within their cells, and the ability to adapt to their environments. It has also been suggested that they are working on making these cells ‘photosynthesise’ like plants. This photosynthetic-like ability would mean that the cells would be able to power themselves. As of yet these iCHELLs do not divide, which as a microbiologist I think is a key concept for something that is living rather than merely surviving. But this experiment does prove a valid point that carbon may not be vital to life on another planet.

But who knows what is out there in the limitless expanse of space? It is quite possible that a variety of different life forms are waiting to be discovered, regardless of whether they are made up of carbon or something else entirely.

Pluto Mark 2?

Emily Sims

In January, Caltech researchers published the paper “Evidence for a Distant Giant Planet in the Solar System” in the Astronomical Journal which detailed evidence for a giant planet with a highly elongated orbit in the outer solar system. This planet has been dubbed ‘Planet Nine’, and is thought to be ten times bigger than Earth, orbits 76 times farther than the sun than Earth, and has a theoretical orbit of 10,000-20,000 years around the sun.


Image Credit: The New Yorker

After absorbing these large statistics, why do scientists believe in the existence of Planet Nine? It has long been thought by scientists that the early solar system started with four planetary cores that pulled the gas around them to form the four gas planets—Jupiter, Saturn, Uranus, and Neptune. Over time, collisions and ejections led to them changing shape and moving to different locations. However, with this theoretical discovery, the possibility of there being five cores rather than four may gain some traction. Planet Nine could represent the fifth core whose potential proximity to Jupiter or Saturn may have led to the distant, eccentric orbit predicted of Planet Nine.

Within the Kuiper Belt, a region of small icy objects in the outer solar system, there are six objects that all line up in a single direction. This orbital alignment could only be maintained by an outside force, such as a planet. The researchers, Konstantin Batygin and Mike Brown, have also noted that Planet Nine is sufficiently large enough to be classified as a planet. Not only is it thought to be a staggering 5000 times the mass of Pluto, evidence appears to suggest that Planet Nine gravitationally dominates a region of the solar system larger than any of the known planets.

“This would be a real ninth planet,” says Mike Brown, “there have only been two true planets discovered since ancient times, and this would be a third. It’s a pretty substantial chunk of our solar system that’s still out there to be found, which is pretty exciting.”

The path to the theoretical discovery was, as is the case with a number of scientific discovery, the product of piqued curiosity and happy accidents. In 2014, a former postdoc of Mike Browns published a paper relating distant objects in the Kuiper Belt with obscure orbital features and the potential presence of a small planet. This kick-started Brown’s curiosity, and together with Batygin, spent a year and a half investigating these distant objects, and quickly found that the six most distant objects followed elliptical orbits that point in the same direction in space (30 degrees downwards to the plane of the eight known planets.) After computer simulations and mathematical modelling, the researchers noticed that if they ran their simulations with a planet in an anti-aligned orbit—the distant Kuiper Belt objects in the simulation assumed the alignment observed in reality. This evidence all points to a new planet- right?

Well, it isn’t actually that simple. Whilst this evidence is exciting, phantom planets are nothing new. “There are dozens of examples where researchers have said there must be another planet to explain some orbital anomaly,” says Mike Brown. For example, Pluto was the original Planet Nine, but its planetary status was disputed after a number of objects of similar size were discovered in the Kuiper Belt. When the International Astronomical Union formally defined the term ‘planet’, Pluto was subsequently reclassified as a dwarf planet.

The evidence is also still theoretical.  Jim Green, NASA’s director of planetary science, cautions that it is still too early to claim that the solar system again has nine planets. Also, I am a little sceptical about the fact that we can image objects outside our solar system, but have not yet found this. The Subaru telescope and the twin 10 metre telescopes in Hawaii are our best chance to directly observe the planet after a few months. Scientists have begun to scan the sky for Planet Nine, using information about its rough orbit.

Planet Nine is an extremely exciting concept and could lead to a surge of interest in astronomy and the potential of our outer solar system, but until the planet is directly observed it cannot be classed as a planet. For now, the sky is the limit.