KIC 8462852 probably sounds like a string of random letters and numbers to you but I'm
willing to bet if you've watched this channel long enough, you've heard it before.
It's the name of a star, also known as Tabby's Star, and it set the internet ablaze a couple
years back when it dimmed in ways nobody could really explain, unless you pinned it on aliens
building massive structures to power their civilization.
Since then though we haven't seen the star's light fade, and so public interest in it did.
But in April of 2017 light levels started dropping again, giving astronomers new clues
to come up with new ideas.
Are any more compelling than a giant energy-harvesting megastructure built by aliens?
I'll let you be the judge of that.
First, a refresher on why Tabby's star is so mysterious.
In 2011 the Kepler Space Telescope observed its light dimmed briefly by 15 percent.
Almost two years later, it temporarily dimmed again, this time by about 22 percent.
Often a drop in a star's light levels is a sign that a planet is passing in front of
it.
But even a planet the size of Jupiter would only block about 1% of the light coming from
a star like this.
And the dimmings caused by planetary transits should be symmetrical and at regular periods,
but these aren't.
They're erratic and all over the place, and can last anywhere from 5 to 80 days.
What we have on our hands gang, is a mystery.
An early explanation from 2015 was comets were knocked from their orbit by a nearby
star and as they plummeted towards Tabby's star, they collided and created a debris cloud.
At the time it was the best fitting solution that didn't involve a vogon constructor
fleet.
Since that idea was first put forward, astronomers have taken a look at data going all the way
back to the 90's --the 1890's that is-- and it turns out the star isn't as bright
as it used to be.
As you'd expect from a star this uncooperative, it's faded erratically, but overall it's
dimmed 16% in the last century.
Comets can't really explain the long term dimming, so that idea is pretty much out.
But maybe the slow fade is evidence of something else.
Some of the first explanations proposed dust from early planets forming, could be the cause,
but Tabby's star is too old to just be forming planets now.
One idea put forward in 2016 is kind of the opposite; instead of a new planet, what we're
seeing is the aftermath of an ex-planet.
One that crashed into the star about 10,000 years ago, causing a flare up that the star
is slowly coming down from, like a long drawn out belch.
That could account for the long term evidence, while orbiting remnants of the planet cause
the more dramatic short term drops in brightness.
After this latest dip, yet another idea has emerged.
What if it's a really really big planet and some buddies?
Trojan asteroids are rocky bodies that share the orbit of a planet.
They hang out in Lagrange points where the gravitational forces between the star and
planet are balanced.
Jupiter has big groups of trojan asteroids so we've seen the phenomenon happen before.
Maybe the Trojans caused those erratic dips, and the massive planet caused some of the
more regular ones.
For this explanation the planet would have to be about 5 times the size of Jupiter though,
and Jupiter is just about as big as a planet can get before it starts fusing hydrogen and
becomes a star.
But the nice thing about this idea is it makes a prediction: if it's true, the Trojan asteroids
will transit again in 2021, followed by the gigantic planet in 2023.
Until then we're just going to keep our eyes on the skies in case KIC 8462852 decides
to do anything else weird.
Special thanks to our sponsor, Domain dot com.
When you buy a domain name from Domain Dot Com, you're taking the first steps in creating
an identity and vision for your brand.
No domain extension will help tell your story like a DOT COM or DOT NET domain name.
Get 15% off Domain Dot Com's already affordable domain names and web hosting when you use
coupon code SEEKER at checkout.
1.4 million of you watched Trace and Astronomer Aaron White talk about Tabby's star two
years ago, but if you weren't among them or want to believe that aliens did it, check
out the original vid here.
So do any of these ideas sway you or are you still voting aliens?
Let us know in the comments, like this video, and don't forget to subscribe so you never
miss another episode of Seeker.
For more infomation >> Laura Kerber : Is life on Mars possible ? - Duration: 9:11. 
Không có nhận xét nào:
Đăng nhận xét