Back at Nine?

I know what you’re thinking. Is Pluto back? Is the one dubbed ‘dwarf’ rejoining us at the top table? Has general opinion won?

In short, no. Sorry to disappoint you all, but Pluto isn’t coming back, at least not for the foreseeable future – it is a dwarf planet, and (barring a sudden change of attitude) won’t be reinstated. That doesn’t mean our home system is stuck at eight planets forever, though.

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Is a ninth planet just waiting to be discovered? (Credit: Kevin Gill)

On the 20th of January (in amongst all the revision) I happened to spot the announcement of a possible (emphasis very much on ‘possible’) ninth planet for the Solar System. Estimated at a mass ten times that of Earth’s, it would be found in the far, far reaches, way beyond the orbit of even Pluto. Neptune, the current outermost planet, orbits 4.5 billion kilometres from the Sun, and takes around 164 years to complete this orbit. It is thought the new planet is 20 times further (on average) than even Neptune, and would take between 10 and 20 thousand years to complete one full orbit.

For context, 10,000 years ago the last ice age had ended not long before, cattle farming had only just been invented, and mammoths still roamed the Earth. This is a time way, way before the Bronze Age, before the civilisations of Egypt, Greece and Rome; before even Mesopotamia and China. If we take the lower bound of that estimate, the planet would have completed only half an orbit since writing was invented. The planet is very, very far away.

At least, it would be – if it had been observed. The team at Caltech have not been spying at this through telescopes; rather, they have been looking at the motions of other far-flung objects, like Sedna, or the not-so-easily-pronounced 2012 VP113. The orbits for these objects appear to line up to one particular side of the Sun, so the team, led by Dr Mike Brown, were curious as to why this should happen; the idea they came up with is the existence of ‘Planet Nine’, with an orbit to the other side of the Sun and thus counterbalancing the much smaller objects being observed.

So what is NASA’s stance on this? Well, it’s fair to say they’re sceptical – and with good reason. Hypotheses about a so-called ‘Planet X’ have been bandied about for over two hundred years, ever since the discovery of Uranus in 1781; Clyde Tombaugh was hunting for this missing planet when he discovered Pluto. But this time, it may be true.

For one thing, Dr Brown is a man who has found many of the most distant objects in the Solar System, including Eris, the discovery of which played a major part in Pluto’s ‘downgrade’ to dwarf planet. Even his twitter handle is @PlutoKiller.

Secondly, models of this region of space have suggested there may be something out there – perhaps not at the size predicted by Caltech, but definitely at least Earth-or-Mars-sized, so almost certainly something that would be classed as a planet.

Finally, Ellen Stofan, chief scientist at NASA, stated in an interview with BBC News: “The intriguing point is: we’ve identified lots of planets (beyond our Solar System) in this category of ‘super-Earth’ with our Kepler telescope; over 5,000 planet candidates. The fact that we don’t have a planet in that size class between Earth and Neptune makes us think, ‘well, maybe we are missing one’, and maybe they’ve predicted it.” This is surely some vindication for those involved with the findings, and does raise a good point – although our star system is in many ways unlike other systems that we’ve found, it must surely share similarities, too. Caltech’s possible discovery could just be one of them.

In other news:

  • Jeff Bezos’ Blue Origin company successfully landed their ‘New Shepard’ rocket back on the ground in November. Launching from Texas, the rocket flew to an altitude of over 100 kilometres (the height of the Karman line, officially marking the boundary between Earth and space), safely descending and landing on the launch pad. This marks a major step in the development of rocket technology, as it is the first time a rocket has been sent to space and been safely returned, potentially reducing the cost of future missions. Rival company SpaceX, led by Elon Musk, raised the bar a month later, achieving the first landing of an orbit-capable rocket, using their ‘Falcon 9’ system. They have since attempted to land a rocket on an ocean barge, though this was unsuccessful as one of the Falcon’s legs failed upon landing, causing the rocket to fall over and explode.
  • In December, Major Tim Peake became the first publicly-funded UK astronaut to represent his country in space. Though others have gone before him, they have either been privately funded, or represented other nations. Since arriving (with minor complications) on board the International Space Station for his six-month stint, he has performed many of an astronaut’s standard duties, including checking on experiments, keeping the station running, and taking data about his health. Having also taken part in a spacewalk (cut short due to water in fellow astronaut Tim Kopra’s helmet), he has also produced numerous videos about his life in space, appearing on both the BBC’s ‘Stargazing Live’ and the Royal Institute’s Christmas lectures. He is due back in June.
  • David Bowie, singer and creator of Ziggy Stardust, passed away aged 69 less than two weeks into 2016, after a
    Image taken from Flickr. License at
    Bowie’s appearance on ‘Aladdin Sane’ (Credit: Marc Wathieu)

    long fight with cancer. Bowie, a science fiction fan, was famous for such hits as ‘Life on Mars’, ‘Starman’ and the instantly recognisable ‘Space Oddity’, along with ‘Let’s Dance’, ‘Heroes’ and collaborations with both Queen (‘Under Pressure’) and Bing Crosby ‘Peace on Earth/Little Drummer Boy’. Bowie’s music was an inspiration to many (including myself) and he will be sorely missed, though his name lives on in a touching tribute by a group of Belgian astronomers – the Bowie asterism consists of seven stars in the shape of a lightning bolt (echoing the cover of his 1973 album ‘Aladdin Sane’), joining a species of spider and an asteroid in being named after the musician. Ex-astronaut Chris Hadfield, who came to worldwide attention in 2013 with a cover of ‘Space Oddity’ recorded aboard the ISS, stated on his website, “With much respect to a genius, a silent moment of reflection: ashes to ashes, dust to stardust. Your brilliance inspired us all. Goodbye Starman.”


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