Exoplanet Astrology: Your Guide to the New Planets

Everyone trusts those great sages of our times, those for whom the intricate secrets of the universe are revealed by the night sky. As wise celestial engineers, the mechanics of the cosmos are obvious to them, the connections between the astronomical and the interpersonal are one and the same. These are people fluent in the language of the stars and skilled at interpreting their enigmatic relationship with humanity, akin to the unfurling of a stellar map of our collective psyche. Scholars all, who undertake years of dedicated study of ancient tomes going back hundreds of years, they have peered into the windows of our souls and seen the nuclear furnaces of the stars themselves.

I’m talking, of course, about astrologers. These wise, charitable, true scientists of our age, who dispense this precious knowledge for only the price of a premium-rate phone call or a column in a lifestyle magazine, to any and all comers. Can you think of a more noble profession?

It pains me however, as a relative newcomer to the field, to note that our astrological maps may be somewhat incomplete! Whilst the stars and constellations – whose graceful dance through our personal lives can be traced with ease by gifted astrologers – are relatively fixed in their positions (on human timescales), those charlatan astronomers have since discovered many, many more planets than the astrological academy may be aware.

Of course, let us not forget the effect of angry Mars on your unwavering passion to join the military, or that of powerful Pluto on your impending rebirth, kidnapping, or initiation into an underground crime syndicate 1. But what of the 1800 exoplanets discovered in the past decade or so? What of their effects on the minutia of your slow, inconsequential trudge to the grave? Well, thankfully, I’ve spent literal minutes conducting my own research on the astrological importance of some of these bodies, and now feel as qualified as any astrologer out there to suggest that you make important and possibly life-changing decisions based on the information I am about to provide to you 2.

The number of exoplanets in each sign of the zodiac, courtesy of the the Planetary Habitability Laboratory.

Here are my predictions for the first four signs! More will follow soon of course.

(Or, alternatively, you could send a text message which will be charged at standard rates, plus £3.50, or visit my pop-up and clickbait-infested website below.)

Sagittarius

The constellation Sagittarius is positively awash with exoplanet-hosting stars, so hold on to your tarot cards because the astrological energy emanating from this sign may well disrupt your centre of balance if this month. HD 179949 b is a ‘hot-Jupiter’ – a massive planet orbiting very close to its parent star, which moves into the sign this week. Like this tumultuous world, you’re feeling increasingly resistant to spectroscopic analyses of your atmosphere, and are keeping evidence of titanium and vanadium oxides close to your chest, possibly to secure a promotion at work. This might seem to be a good strategy now, but your low bond albedo and furnace-like temperatures may make you hot under the collar – a prime target for infrared studies.

Capricorn

This month you may notice a feeling of cold eccentricity creeping into the trivialities of your everyday life. This is probably because of the effect of HD 204941 b on the goat sign this month – a frigid Neptunian planet with an off-center orbit who seems destined to cause a cold-spell in your love life. Detected by the sensitive HARPS instrument, like this planet you need to warm up to those close to you, especially if they’re astronomically massive spheres of super-heated plasma undergoing nuclear fusion, and accept that your radial velocity is discernible from light years away. You have to learn to embrace it and move on! Try sublimating a relaxing herbal or chi tea into your chaotic atmosphere as you near aphelion to help you unwind.

Aquarius

Good news! You may find yourself appreciating your relationships with your family members this month. The red-dwarf Gliese 876 is ascendant in this sign and like its extended family of four exoplanets, you’ll notice your loved-ones adopting a stable, coplanar Laplace resonance of 1:2:4, which will bring you neither further away nor any closer together, for the next 4 billion years at least. Be aware of co-workers and friends however, who like Gliese 876 itself will react in a highly unpredictable ways to your new-found stability, and will be prone to X-ray emissions. Steer clear girlfriend!

Pisces

Pisces is inundated with exoplanets, all of whom are jostling and vying for an chance to directly affect the fleeting existence of a billion apes on a tiny planet several light years distant. Can you not feel them? This month, like the gravitational interaction between Saturn-sized exoplanet HD 3651 b and its distant brown dwarf companion, you’ll feel like people on your extremely distant peripheries are disrupting your already highly eccentric orbit as a Pisces over the coming weeks. Just as NASA’s Spitzer Space Telescope directly imaged this system in 2006, so you’ll have the opportunity to compare existing theoretical evolutionary models to these substellar naysayers as we near Christmas. Just ensure you take some time out of your 62 day year for yourself!

Well, that’s all for now exoplanet astrology fans, but not to worry, I’ll be back with my readings of the remaining signs once I’ve had a chance to adjust my flux capacitor and have rechecked my calculations. Until then, remember: the whole universe is watching you. All the time. Wherever you are, and what ever you’re doing.

This was a guest post by the worlds foremost exoplanet astrologer, Dr Jawbone Hyurns. Follow him on Twitter for regular astrological and exoplanetary updates!

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1 In case it wasn’t obvious by now, this post is satire. However, these particular statements are actually based on stuff found online, where it was claimed Pluto is the planet of terrorism, death, obsession and kidnapping. Pluto’s taking its demotion to minor planet pretty hard it seems, and the astrologers still haven’t caught up on its new classification. I did consider including references, but felt an ethical obligation not to provide traffic to these sites. I took a virtual bath afterwards.

2 Thanks, as always, to the Planetary Habitability Laboratory for their exoplanet astrology resources!

Dead Stars Reveal Mysteries of Planet Formation

       

This is a guest post by David Wilson, a PhD student in the Astronomy and Astrophysics group at the University of Warwick, where he studies the remains of planetary systems around white dwarfs (see below!). He can be found on Twitter and blogs about various astronomy topics at Stuff About Space.

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Twenty seven years ago astronomers noticed something strange about the white dwarf star GD29-38.

White dwarfs are dead stars, the burnt out carbon cores of stars like our Sun which have exhausted their hydrogen fuel; incredibly dense, incredibly hot balls of matter roughly the size of the Earth. Because of their high temperature, tens of thousands of degrees, all white dwarfs glow blue.

But the light from GD 29-38 wasn’t just blue. When it was split into a spectrum, separated into a rainbow of separate colours, there seemed to be something else there. Something shining with an infrared light, beyond the range of our eyesight.

Initially the discovers were excited, as the red light could have come from an orbiting brown dwarf, a mysterious object several times bigger than a planet but much smaller than a star. But both the white dwarf and the infrared source were pulsating slightly, periodically getting brighter and dimmer. If the red light was from a separate object, then it shouldn’t have pulsed in time with the white dwarf.

An asteroid plummets to its doom around the white dwarf GD 29-38. Studying the debris left from these asteroids can reveal the chemical composition of exoplanets. Image Credit: NASA

The spectrum also revealed metals in the white dwarf’s atmosphere, heavy elements like calcium, magnesium and iron. These were also out of place, as white dwarfs have such a strong gravity that anything heavier than hydrogen or helium should have sunk down into their cores long ago. The metals must be falling onto the white dwarf from the space around it- but how did they get there?

It took until 2003 for the origin of the mysterious infrared glow to be found, during which time many more white dwarfs with similar red spectra and metal polluted atmospheres were found. The explanation was that the infrared light is coming from a disc of dusty debris surrounding the white dwarf.

This debris was formed from the wreckage of an asteroid, leftover from when GD29-38 was a Sun-like star with its own system of planets. The dust in the disc rains down onto the white dwarf, explaining the metals we see in the atmosphere.

The spectrum of GD 29-38. Along the bottom is its wavelength, or colour, going from blue on the left to invisible infrared on the right. The vertical axis shows how bright the white dwarf is at each wavelength. The difference between the blue white dwarf and red dust cloud can be clearly seen. Image Credit: NASA

The spectrum of GD 29-38. Along the bottom is its wavelength, or colour, going from blue on the left to invisible infrared on the right. The vertical axis shows how bright the white dwarf is at each wavelength. The difference between the blue white dwarf and red dust cloud can be clearly seen. Image Credit: NASA

The story of how the debris disc got there is a result of the turbulent formation of the white dwarf. As it runs out of fuel a star swells up to a huge red giant, then blows away roughly half of its mass in an immense stellar wind, leaving the tiny white dwarf core.

With the gravitational force at its heart cut in two, the system of planets around the dying star is thrown into chaos. Planets begin to migrate outwards, trying to reach orbits twice as far away from the central star as before. As they do this, they risk coming into close contact with each other.

Some of the planets survive these encounters and carry on as they are. Others, especially when a big Jupiter sized planet is involved, are thrown out of the system into the depths of interstellar space. And some are scattered into the centre of the system towards the white dwarf.

These unlucky asteroids and dwarf planets fall in towards the white dwarf until they reach a point known as the tidal disruption radius. There the tidal force, the difference in gravitational pull between the parts of the asteroid nearest the white dwarf and the areas further away, becomes so great that the asteroid is ripped apart, forming the dusty debris disc that we see as an infrared glow.

The discovery of this process lead to an important conclusion. As the dust rains down onto the white dwarf it becomes visible to our telescopes. If we can measure what metals there are, and how much of each there is, then we can reveal the chemical composition of the asteroid or planet that formed the disc. We can ask, and answer, the question: “What are planets made of?”

Two decades ago we only knew about the eight planets in our solar system (Pluto was never a planet, it was just mislabelled). Now we know of over a thousand planets, new worlds orbiting hundreds of stars. Through our telescopes we can measure the size of these planets, what their masses are, and even in some cases get a glimpse into their atmospheres.

But we can’t find out what they’re made of, what the geology of these newly discovered planets is like. This means that we don’t know for sure if the way that the rocky planets are built in our solar system, the particular mix of iron, oxygen, magnesium, silicon and other chemicals that make up the Earth and its neighbours, is the way all planets are built.

The metal polluted white dwarfs form a perfect laboratory, presenting us with rocky objects that have broken apart into their chemical components. By observing as many as we can, we can begin to explore the chemical diversity of planets and planetary systems. We can see if the way our planets are built is the normal way to construct a planet, or whether Earth is even more unique than we thought.

To date we’ve discovered around a dozen white dwarfs with enough chemicals to compare their systems in detail with our own. So far, they look fairly similar to the Earth, a hopeful sign. But we need many more to truly explore this area, and over the next few years myself and others will be scouring the sky, using the Hubble Space Telescope above us and an array of telescopes on the ground. We will find more metal polluted white dwarfs, measure the chemicals of the planetary debris around them, and begin to explore in detail what things you need to build a planet.

The Atmospheric Mirror

‘Earthrise’ : A blue marble, floating in a sea of blackness.

 

When viewed from space, the Earth glows like a blue marble under the light of the distant Sun. Azure oceans lap against the jagged coastlines and pale clouds swirl gracefully across its face, temporarily obscuring from view the brown-green landmasses beneath. From this vantage point, there is little to suggest that intelligent bipedal apes are scuttling around the coasts; confident of their centrality to all the workings of the cosmos, yet mostly unaware of the intricate complexities of its operation.

With the exception of five hundred  operational satellites amidst a sea of orbital debris, one permanently occupied space station in low Earth orbit and two intrepid robotic explorers on the planet next door (Opportunity and Curiosity), humans have little visible presence outside of the Earth. In spite of our delusions of grandeur, we assume that no evidence of our global civilisation could be detected from light-year distances.

However, if we imagine that somewhere in the menagerie of stars that make up our local neighbourhood in the Milky Way, on a planet not too dissimilar from ours, an alien astronomer was perched at his (or her) telescope one night staring out into the dark when our Solar System happened into view. What would they see? Just another star on their survey, if relatively young and brighter than most, but perhaps one of many observed that evening. Initially, the blinding glare of the Sun would obscure our family of planets from direct view. Luckily, there are a number of ways to circumvent this problem. Using indirect planet detection techniques familiar to us such as radial velocity measurements or transit timings, the planetary companions of this curious yellow dwarf star are revealed:  four gas giants and four smaller worlds. If the exo-astronomer ran their observations through their superior spectrometer however, chances are they may be intrigued by the results from one tiny blue planet in the orbit of this humdrum star.

Spectrometers measure the properties of light, first emitted by stars but then altered by the constituent gases of the planetary atmospheres through which the beam passes on the way to the receiving instrument. Different gases absorb light at different wavelengths to produce characteristic spectra and the composition of the atmosphere mirrored in the light can be teased out of the noise with sufficient skill. The high levels of water vapour, oxygen, methane and other gases associated with biological activity discovered in the atmosphere of this planet should result in the alien equivalent of a raised eyebrow. Methane is a ‘reduced’ gas and is usually rapidly destroyed in the presence of oxygen, meaning that detecting an appreciable amount of both may suggest that a biological mechanism is responsible for their continual replenishment. This mismatch is identified as a ‘biosignature‘ – a sign that this planet may harbour life.

Planetary atmospheres are something we are all intimately familiar with. The Earth’s is flush with life-giving oxygen, greenhouse gases essential (in the right balance) to maintaining a clement climate and an ozone layer that shields us from the Sun’s harmful rays. Most of us will never leave its gaseous embrace, and without it life would be extremely difficult. However, we take for granted the atmosphere’s ability to act as a mirror of our activities detectable from astronomical distances, able to reflect the unique signatures of the gases injected into it and hold them there for those with the correct instruments to see.

Further studies by the inquisitive alien astronomer would reveal a soup of exotic chemicals in the atmosphere of this distant little planet: increasing levels of carbon dioxide along with a suite of destructive, industrially produced compounds like chlorofluorocarbons (CFCs). There is no known biological pathway for producing CFCs, so their detection in the atmosphere of this planet is a strong indication of the activities of industry. They have struck gold (or the equivalently rare element on their planet) by discovering compelling evidence for the existence of another technologically advanced species. In doing so, they may have forever altered the way their civilisation views itself – one of perhaps many in a vast, galactic family.

Cloaked in an imaginative example, this is the theory that lies behind using spectroscopy as a method of detecting life, and perhaps even advanced civilisations, across the depths of space. Two promising space telescopes, TPF (NASA) and Darwin (ESA), were cancelled due to budgetary constraints, so for now at least interstellar planetary spectroscopy remains out of our grasp. However, the hope is that instruments of the near-future will be able to examine the atmospheres of exoplanets to search for these signs of life. Until they can, it might be worth remembering that we might not be the only ones able to gaze into the Earth’s atmospheric mirror.

Perhaps we should try to keep it clean?