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extraordinary claims require extraordinary evidence and my
responsibility as an astronomer to remind people that alien hypotheses
should always be a last resort I want to tell you a story about that involves
data from a national mission ordinary people and one of the most extraordinary
stars in our galaxy began in 2009 with the launch of NASA's Kepler Mission
Kepler's main scientific objective was to find planets outside our solar system
it did this by staring at a single field in the sky this one with all the tiny
boxes and then this one field monitor the brightness of over a hundred and
fifty thousand stars continuously for four years taking a datapoint every 30
minutes it was looking for what astronomers call transit this is where
the planet's orbit is aligned in our line of sight just so that the planet
crosses in front of a star and when this happens it blocks out a tiny bit of
starlight which you can see as a dip into the team at nasa had developed very
sophisticated computers to search for transit and all the Kepler data at the
same time of the first data release astronomers at Yale were wondering an
interesting thing what if computers miss something so we launched the citizen
science project called planet hunters to have people look at the same data the
human brain has an amazing ability for pattern recognition sometimes even
better than a computer however there is a lot of skepticism around this my
colleague Debra Fischer founder the planet hunters project to the people of
a time are saying you're crazy
there's no way that a computer will missus signal and so is the classic
human vs machine and if we found one planet will be thrilled when i join the
team for years ago we had already found a couple and today with the help of over
300,000 science enthusiasts we have found dozens and we've also found one of
the most mysterious stars in our galaxy so to understand this let me show you
what a normal transit a couple of data looks like and this crash on the left
hand side you have the amount of light and on the bottom is time the white line
is like just from the star
astronomers Carl a light curve know when a planet transits the start blocks out a
bit little bit this light and the depth of this transit reflexively size of the
object itself and so for example if you take Jupiter Uranus don't get much
bigger than Jupiter Jupiter will make it one percent drop in a star's brightness
earth on the other hand is 11 times smaller to jupiter and signal is barely
visible in the data to back to our mystery a few years ago hundreds were
sifting through data looking for transit and they spotted a mysterious signal
coming from the star KIC 8462 852 the observations in May of 2009 were the
first they spotted in they started talking about this discussion tours they
said an object like Jupiter will make a drop like this in the star's light but
they're also saying it was giant UC transits normally only last for a few
hours and this one lasted for almost a week they were also say that it looks
asymmetric meaning that instead of the clean U-shaped it that we saw Jupiter
had this strange that you can see on the left side this indicate that whatever is
getting in the way and blocking the Starlight was not circular like a planet
there are few more deaths that happened but for a couple years it was pretty
quiet and then
in March of 2011 we see this the stars like drops by a whole 15 percent this is
huge compared to a planet which would only make a 1% drop we describe this
feature as both smooth and clean it also is asymmetric having a gradual did that
last week and it snaps right back up to normal just a matter of days and again
after this
not much happens until February of 2013 things to start to get really crazy
there is a huge complex of dips and the light curve that appear and they last
for like a hundred days all the way up into the Kepler mission sent these steps
have variable shakes summer very sharp in summer abroad and they also have
variable durations some last just for a day or two and some for more than a week
and there's also up-and-down trends within some of these debts almost like
several independent events were superimposed on top of each other and at
this time
this star drops in its brightness over 20% this means that whatever is blocking
its life has an area of over a thousand times the area of our planet Earth this
is truly remarkable and so the citizen scientists when they saw this they
notified the science team that they found something weird enough that it
might be worth following up and so on the same team looked at it we're like
there's probably just something wrong with the data but we looked really
really really hard and the data were good and so what was happening had to be
out your physical meaning that something in space was getting in the way of
blocking starlight and so at this point we set out to learn everything we could
about the start to see if we can find any clues to what was going on and the
citizen scientist who helped us in this discovery they joined along for the ride
watching science in action firsthand
where somebody said well you know what it is star was actually very young and
it still have the cloud of material was born from surrounding it and then
somebody else said what started Rd form planets into these planets had collided
similar to the earth-moon forming of it
these theories could explain part of the data but the difficulties were that the
star showed no signs of being young and there was no glow from any of the
material that was heated up by the star's light and you would expect this
if the stars young or if there was a collision I don't want to dust was
produced and so somebody out there well how about a huge swarm of comments that
are passing by the star in a very elliptical orbit
well this is actually consistent with our observations but I agree it does
feel a little contrived you see it would take hundreds of comments to reproduce
what we are observing and these are only the comments that happened to pass
between us from the start and so in reality we're talking thousands to tens
of thousands of comments but of all the bad ideas we had this one was the best
and so we went ahead and publish their findings but let me tell you this is one
of the hardest papers I ever root scientists are meant to publish results
in this situation was far from that and so we decided to give it a catchy title
we called it whereas the flux I would like to view the acronym
the story around the same time I was writing this paper I met with a
colleague of mine Jason right and he was also writing a paper on Kepler data and
he was saying that with Kepler's extreme precision it could actually detect alien
megastructures around stars but it did it and then I showed him this weird data
that are citizen scientists have found and he said to me to be no I have to
rewrite my paper for your natural explanations were weak and we were
curious out so we had to find a way to rule out aliens so together we commenced
a colleague of ours to search for extraterrestrial intelligence that this
would be an extraordinary target to pursue a proposal to observe the star
with the world's largest radio telescope at the Green Bank Observatory a couple
months later news of this proposal got leaked to the press and now there are
thousands of articles over 10,000 articles on this store alone and if you
search Google Images this is what you'll find now you may be wondering Ok Tedi
will how do I lian's actually explain this like her ok well imagine the
civilization that's much more advanced than our own in this hypothetical
circumstance this civilization would have exhausted the energy supply of
their home planet so where did they get more energy
well they have a host are just like we have a son and so if they are able to
capture more energy from this star than that would solve their energy needs so
they were going structures he's giant mega structures like ginormous solar
panels are called tyson's fears of this image above is the president of Dyson
Sphere it's really hard to provide perspective on the van
axis of these things but you can think of it this way the earth-moon distance
is a quarter of a million miles
the simplest element and one of these structures is a hundred times that size
there are enormous and now imagine one of these structures in motion around the
star you can see how will produce anomalies in the data such as even
unnatural looking dips but it remains but even alien megastructures cannot
defy the laws of physics you see anything that uses a lot of energy is
going to produce heat and we don't observe this but it could be something
as simple as they're just rewriting it away in another direction just not worth
another idea that's one of my personal favorites is that we just witnessed an
interplanetary space battle and the catastrophic destruction of a planet now
I admit that this will produce a lot it does that we don't observe but if we r
Rd invoking aliens and this explanation then who's to say they didn't officially
clean up all this mess for recycling purposes you can see how this quickly
captures your imagination they have it four in a situation that could be a
natural phenomena we don't understand or an alien technology we don't understand
personally as a scientist my money's on the natural explanation but don't get me
wrong I do think would be awesome to find aliens either way there's something
new and really interesting to discover so what happens next we need to continue
to observe the start to learn out more what's happening a professional
astronomers like me we have limited resources for this kind of thing and
Kepler's onto a different mission and I'm happy to say
that once again
citizen scientists have come in and save the day you see this time amateur
astronomers with their backyard telescopes stepped up immediately and
started observing the start nightly at their own facilities and I am so excited
to see what their side what's amazing to me is that this star would have never
been found by computers cuz we just went looking for something like this and
what's more exciting is that there's more data to come there are new missions
that are coming up that are observing millions of more stars all over the sky
and to think what will it mean when we find another star like this and what
will it mean if we don't find another star like this
thank you