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Tabby's star is dimming at an incredible rate

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Re: Tabby's star is dimming at an incredible rate

#151

Post by rralian »

david-given wrote: post #71
peonicles wrote: post #59

Earlier quoted context omitted.

There's a comment [1] in the other reddit thread that somewhat rules this out. > That doesn't even make sense when you're flying within the Solar System. Stuff moves, so you have to fly towards where it's going to be, not where it is. > The star is far enough away to be treated as a point source, with its light forming an apparent cone with the Earth's diameter. It doesn't intuitively make sense, at least to me, that…

You just need a big enough ship. A while back I had a plan for a science fiction setting: an inter galactic ship is approach Earth. The people who sent it thought big, and as a result the ship has at its core an enclosed star (a miniature Dyson Sphere) as a gravitational anchor and power source, and round it is orbiting a vast swarm of asteroids and habitats with a few million times the living space of Earth, inside…

Keep it up! I'd read that.

Re: Tabby's star is dimming at an incredible rate

#152

Post by manarth »

whage wrote: post #58
fjarlq wrote: post #42

Earlier quoted context omitted.

Reddit user sigbjoernwilderness's idea is pretty wild... can it be easily ruled out? > Is this the last remaining explanation after Montet/Simon? > The dimming comes from the shadow of a spaceship traveling on an (almost) straight line from KIC8462852 to Earth. The slow continuous dimming results from the increase of the apparent size of the approaching ship while Earth/Kepler is in the penumbra. The irregular dips h…

Do spaceships travel in a straight line? I thought their trajectories are heavily curved in really weird ways due to the garvities of stars and planets around them. Please enlighten me!

It depends on the frame of reference, which can be somewhat arbitrary.

A ship can sail a straight line from Falmouth to Boston, but that motion can be described as an arc because of the curvature of the Earth. Add in the motion of Earth's orbit, and the shape of that motion changes again. Add in the Solar System's motion relative to the Galactic Centre, and it's yet another shape.

It's all a matter of perspective :-)

Re: Tabby's star is dimming at an incredible rate

#153

Post by api »

bitJericho wrote: post #91
kuschku wrote: post #82

Earlier quoted context omitted.

no, @api is right - you're orbiting the galactic center for a while. Similar how transfer from earth to mars works via a solar orbit. So, yes, you have to include orbital mechanics, not just straight lines.

I didn't say there's no need to consider orbital mechanics. I said taking a route through the galactic center is not a realistic scenario.

I didn't mean through the center, just orbiting it. Look up a Hohmann transfer. I was just saying it wouldn't be direct.

Re: Tabby's star is dimming at an incredible rate

#154

Post by andrepd »

mjevans wrote: post #34
jerf wrote: post #22

Earlier quoted context omitted.

"Well whatever it is, we probably have 1000+ years to save ourselves right?" No. That time has already passed. If we see signs that the star will go nova "in one year", we have one year, not 1481. The popular idea that we see "the past" in the sky is not really the best way to think about it. It is far more accurate to say that there is no such thing as "the" present, and what we see in the sky really is our present.…

From an intelligent life angle, what would really save us is that, aside from a number of planets to observe, we haven't really been all that interesting until the last 100-200 years; when we started actually emitting signs of intelligent life in to space.

Hmm, that's actually not true. For example a spectroscopical analysis of the composition of be earth's atmosphere would reveal very unusual properties which would be a sure telling sign of photosynthesis, and that has been occurring for billions of years.

Re: Tabby's star is dimming at an incredible rate

#155

Post by mk-61 »

david-given wrote: post #71
peonicles wrote: post #59

Earlier quoted context omitted.

There's a comment [1] in the other reddit thread that somewhat rules this out. > That doesn't even make sense when you're flying within the Solar System. Stuff moves, so you have to fly towards where it's going to be, not where it is. > The star is far enough away to be treated as a point source, with its light forming an apparent cone with the Earth's diameter. It doesn't intuitively make sense, at least to me, that…

You just need a big enough ship. A while back I had a plan for a science fiction setting: an inter galactic ship is approach Earth. The people who sent it thought big, and as a result the ship has at its core an enclosed star (a miniature Dyson Sphere) as a gravitational anchor and power source, and round it is orbiting a vast swarm of asteroids and habitats with a few million times the living space of Earth, inside…

Yet another book recommendation:

Terre en fuite (Fleeing Earth) (1960) by François Bordes (pen name Francis Carsac), though, there is still no translation in english of that gem, where Earth and Venus was converted to spaceships for running away from exploding Sun!

Re: Tabby's star is dimming at an incredible rate

#156

Post by kordless »

david-given wrote: post #71
peonicles wrote: post #59

Earlier quoted context omitted.

There's a comment [1] in the other reddit thread that somewhat rules this out. > That doesn't even make sense when you're flying within the Solar System. Stuff moves, so you have to fly towards where it's going to be, not where it is. > The star is far enough away to be treated as a point source, with its light forming an apparent cone with the Earth's diameter. It doesn't intuitively make sense, at least to me, that…

You just need a big enough ship. A while back I had a plan for a science fiction setting: an inter galactic ship is approach Earth. The people who sent it thought big, and as a result the ship has at its core an enclosed star (a miniature Dyson Sphere) as a gravitational anchor and power source, and round it is orbiting a vast swarm of asteroids and habitats with a few million times the living space of Earth, inside…

> if this turns out to be true, I want credit

You cool if we blame you too? :)

Re: Tabby's star is dimming at an incredible rate

#157

Post by pavel_lishin »

mkstowegnv wrote: post #110
Normal_gaussian wrote: post #86

Earlier quoted context omitted.

It also assumes that outside observers have the same difficulty understanding the make-up and probable evolution of a system as we do. If they were able to observe that Earth would have some properties they were interested in, or would be a likely candidate for such, then they wouldn't need us to announce our presence to guess it.

IMHO the aliens will not be specifically seeking life that is intelligent. Singularities and interstellar traveling alien civilizations share a problem. If one is in essence immortal the only purpose that can endure forever is the pursuit of new knowledge. Even if alien entities are able to learn all there is to know about all the other sciences, biology will be inexhaustible as the novel patterns that can be produce…

> If one is in essence immortal the only purpose that can endure forever is the pursuit of new knowledge.

That's making a lot of assumptions about alien psychology, believing they're going to have the same goals as us. Why not

1. Propagation of your species, forever

2. Expansion of your territory until the entire Universe is yours

3. Endless pursuit of pleasure

4. Propagating religious beliefs, or something we'd recognize as such.

5. Escaping this Universe, which will eventually end.

Re: Tabby's star is dimming at an incredible rate

#158

Post by hasenj »

peonicles wrote: post #59
fjarlq wrote: post #42

Earlier quoted context omitted.

Reddit user sigbjoernwilderness's idea is pretty wild... can it be easily ruled out? > Is this the last remaining explanation after Montet/Simon? > The dimming comes from the shadow of a spaceship traveling on an (almost) straight line from KIC8462852 to Earth. The slow continuous dimming results from the increase of the apparent size of the approaching ship while Earth/Kepler is in the penumbra. The irregular dips h…

There's a comment [1] in the other reddit thread that somewhat rules this out. > That doesn't even make sense when you're flying within the Solar System. Stuff moves, so you have to fly towards where it's going to be, not where it is. > The star is far enough away to be treated as a point source, with its light forming an apparent cone with the Earth's diameter. It doesn't intuitively make sense, at least to me, that…

Maybe they are taking the long about route on purpose to let us know about their arrival!

Re: Tabby's star is dimming at an incredible rate

#159

Post by freyir »

jerf wrote: post #22
lucb1e wrote: post #20

Earlier quoted context omitted.

Well whatever it is, we probably have 1000+ years to save ourselves right? If whatever caused it comes at us at 50% light speed, which sounds unlikely given how fast that already is, we'd still have 700 years. I'm pretty sure that if human's resources were suddenly all turned towards getting the hell out of here, we could certainly pull it off for a good part of the population in a few hundred years. Whether we'd eve…

"Well whatever it is, we probably have 1000+ years to save ourselves right?" No. That time has already passed. If we see signs that the star will go nova "in one year", we have one year, not 1481. The popular idea that we see "the past" in the sky is not really the best way to think about it. It is far more accurate to say that there is no such thing as "the" present, and what we see in the sky really is our present.…

> No. That time has already passed. If we see signs that the star will go nova "in one year", we have one year, not 1481.

He specifically referred to something traveling at half of the speed of light, in which case it would arrive in >=1480 years not one.

Re: Tabby's star is dimming at an incredible rate

#160

Post by sitkack »

amelius wrote: post #129

Could it have been hit by a large planet that lost its orbit somehow (perhaps from another system)? (And out of interest, is this an event that has been recorded before?)

Are you saying we looking the edge end of an Accretion Disk[0] ?

https://en.wikipedia.org/wiki/Accretion_disk

Two planets collide, forming a huge mess, that mess continues to collide with itself in a chain reaction. If the rings of saturn surrounded a star, what would that star look like when viewed edge on? Do the rings precess? What can we say about the size of the object in the ring and how will the ring structure evolve over time?

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