KIC8462842

There’s Something About KIC8462852

F-type star discovered by the Kepler telescope, 1500 light years from us.

Kepler Telescope

16thc, Father was a mercenary, mother was a healer and herbalist. Astronomy and astrology were entwined, so herbalism and science not too strange bedfellows. Noble (grandfather lord mayor of Weil de Stadt (Stuttgart) but poor.

Early work included Mysterium Cosmographicum

Tried to uncover God’s geometrical plan for the universe, wrapping the orbits of the planets (only six at that time) in platonic solids, an octahedron, icosahedron, dodecahedron, tetrahedron, cube.

Theological convictions that the universe itself was an image of God, with the Sun corresponding to the Father, the stellar sphere to the Son, and the intervening space between to the Holy Spirit. Published by the Tübingen University pending removal of all that Bible stuff.

https://upload.wikimedia.org/wikipedia/commons/thumb/2/25/Kepler-solar-system-2.png/220px-Kepler-solar-system-2.png

Worked with Tycho Brahe, who guarded data closely so Kepler managed to do more after Brahe died, as he nicked all his work.

Later worked on Astronomiae Pars Optica, the optical part of astronomy.

Laws of light and how we actually see things.

Worked with Galileo Galilei, sort of unilaterally. Galileo published observations and sought Kepler’s reputation-boosting opinion; Kepler said ‘wow!’ and endorsed him, bro-style.

Kepler then published his own observations in Glileo’s support, to which Galileo didn’t bother to respond. Kepler is said to have been ‘bummed out’.

So then he borrowed his buddy Duke Ernest of Cologne’s telescope and made his own experiments in optics, eventually coming up with a method using two convex lenses which is called the astronomical or Keplerian telescope. So I guess that solves the mystery of the naming of the Kepler telescope.

Footnote - He wrote Somnium, or The Dream, which tries to prove a case for heliocentrism by describing what practical astronomy might be like on another planet.

First science fiction novel, basically, part allegory, part autobiography.

Mainly because of a part where the (autobiographical) narrator’s mother summons a demon to learn how to travel through space, Kepler’s (literal) mum was tried for being a witch.

Once she was acquitted (14 months in prison), Kepler added two-hundred and twenty three footnotes to the story (much longer than the original text) which mainly said ALLEGORY in large letters.

F-type star

Standard alphabetical sequence of 7 stellar types based on absorption spectra, O - M. Yes, O, B, A, F, G, K, M. Standard. This is also a classification of temperature.

O is hot, M is cool, where hot is 20000k, cool is 2000k. Sol is G2 V, 6000k.

There’s also class I to V, determining size. V is dwarf, the we go straight from dwarf to giant, and then way out there to supergiant which is a classifcation system starbucks rejected.

KIC 8462852 is F3 V/IV, so a bit hotter than Sol, 7400k, 6 times brighter than Sol, and a bit bigger than Sol.

Transit

Planets orbiting in front of a star cause a regular periodic dimming, something of the order of 1/10,000th of the star’s brightness lasting between 1 and 16 hours.

If the observation is repeated, then it’s probably something between the star and the telescope.

Then clever people can work out the size of the planet (from orbital period based on the known mass of the star, which is based on the spectrum I think) and see if it’s probably a rocky planet rather than a gas giant in the habitable zone.

Only works if the orbital plane of the solar system is in line with ours. Probability 0.5% for earth-like planets around sun-like stars.

Kepler needs to look at 150,000 stars to get statistically significant results, and looks at an area of space equivalent to holding your hand out at arm’s length (not much, but about 100 times more than most astronomical telescopes in terms of square degrees).

It’s the blunderbuss of astronomical observation, and it has stared into this region of space for eighty months, never blinking.

It’s produced so much data from simultaneously staring at 150,000 star for nearly seven years that the Kepler astronomers founded Planet Hunters, a group of citizen scientists, to look for patterns.

Human eye is still better than algorithms at looking for patterns.

Interesting light patterns found through the transit method, but this time the light was dimming more and for longer periods in an aperiodic way.

Trek fans leapt on this and said IT’S A DYSON SPHERE EHMERGERD.

Freeman Dyson

More than just an allegorical name, dyson came up with the idea that if your civilisation was superbad then you’d colonise stars either for habitation or energy by building gigantic hollow spheres around them, or swarms of orbiting solar panels and then lap up free energy or massive living spaces for ever.

He later said his theory was a bit of a joke, but it didn’t stop there being a Star Trek episode about it which apparently captured the imagination of some people who leapt on this paper about KIC.

Dyson sphere

KIC was dipping a lot more than 1/10,000th (more like 20%) and the dipping lasted between 5 and 80 days. That’s a lot more of everything than a planetary transit would display, so scientific consensus was ‘it’s a bit weird’.

Actually scientific consensus said it’s comet fragments but science fiction consensus ignored that, optimistically.

Arguments against it being a Dyson sphere are that the sphere would totally envelop the star if it wasn’t currently (well, 1500 years ago) under construction, and the odds of finding a stellar building site are astronomical.

To make a Dyson sphere you disassemble a nearby planet to get the raw material. It would take about 31 years to disassemble Mercury to make a partial Dyson shell around Sol, so say it would take 1000 years to completely cover KIC, which is 1.46 solar masses.

The odds of us seeing an incomplete shell that takes 1000 years to build around a 4.1 billion year old star are one in 4.1 million.

That is, even if one of the 150,000 stars Kepler is looking at has been bought up by alien power plant manufacturers.

More likely? A star close to KIC (130bn ly) disturbed material from KIC’s Oort cloud (where all the comets live) and sent them into the star, or at least between Kepler and KIC, which would block quite a lot of light, randomly. Assuming they were big comets.

Assuming big comets don’t exist, aliens are much more likely.

Except not. NASA came bowling in in its size twelves, and used the Spitzer space telescope which can do infra-red.

If the occlusions are caused by solar panels then they’ll be hot, and emit large amounts of IR radiation.

They were not hot. They were cold. Cold like comets.

Oh well.



Published

11 January 2017