Comments on: Spiral harm

By: forrest noble

forrest noble — Wed, 19 Dec 2007 21:56:34 +0000

drazel, It’s that global cooling– the dimming of the sun be polution that will get us–didn’t you see the movie.

By: drazil

drazil — Wed, 19 Dec 2007 04:22:24 +0000

I think global warming will cause the earth to be inhospitable for life long before the 200 million years

By: forrest noble

forrest noble — Thu, 15 Nov 2007 05:37:15 +0000

Yawning Angel, don’t worry about the Great Attracter. In 100 billion years or sooner the sun will have long since burned out probably– and our species, if it’s still around, will have had plenty of time to star hop, galaxy hop many times as well, or maybe travel beyond the now visible universe– that too is thinking big, without resorting to science fiction I believe.

By: Yawning Angel

Yawning Angel — Wed, 14 Nov 2007 07:10:38 +0000

I think we should be able to see a Bok Globule Long, long before it starts to come our way, it ours its.
These figures are ALL rather rubbery anyway. Carbon and other methods of dating are really litle better than Guesses any way. Or so I’m am told.
And, WHAT ABOUT the BIG Picture???? You talk about 4-6 billion years hence but thats nuthing on a Cosmic Scale.
WhAT i WANT TO KNOW IS WHAT ABOUT THE GREAT Attracter??
Aren’t We ALL heading towards the Virgo cluster and smash into 100′s of Galaxies in the next 100 Billion years or So????
Think Big You People!

By: Seed's Daily Zeitgeist: 11/9/2007 - General Science

Seed's Daily Zeitgeist: 11/9/2007 - General Science — Mon, 12 Nov 2007 22:10:06 +0000

[...] Spiral harm Something else that will (almost certainly not) kill us all. [...]

By: Loaf Of Bread

Loaf Of Bread — Fri, 09 Nov 2007 19:55:16 +0000

Hey, 200 million years is a fairly nice chunk of time in evolutionary terms. Wasn’t it only about 60 million years ago that the dinosaurs were running the show? We could nuke ourselves tomorrow, and there would still be lots of time for some other intelligent species to evolve and figure out how to get away from the third rock from the sun.

By: The Centipede

The Centipede — Fri, 09 Nov 2007 18:28:38 +0000

For some reason I’m getting the distinctly amusing mental image of deploying Space Roombas to suck up the nasty bad space dust bunnies…

By: SteveInNC

SteveInNC — Fri, 09 Nov 2007 18:21:11 +0000

I’m fairly sure that G-type stars like the sun have very little matter exchange between the core and the convective zone, so the carbon would stay in the outer layer (http://en.wikipedia.org/wiki/Sun#Structure), though I’m sure it would have some effect on luminosity or color. Small stars (M-class) are believed to be fully convective, though their temperature would be too low for the carbon cycle to occur.

By: !AstralProjectile

!AstralProjectile — Fri, 09 Nov 2007 17:44:36 +0000

All the carbon in the gas cloud will percolate into the core of the sun, increasing the contribution of the carbon cycle to the overall fusion reaction, thereby causing the sun to go nova!! :-0 (Theory ripped of from Asimov’s “The Currents of Space”)

Any of you folks read James Tiptree’s novella “Up the walls of the World”? Pretty good read with a parsecs-long, slightly-denser-than-a-vacuum critter that can alter time and cause suns to go nova?

By: Lab Lemming

Lab Lemming — Fri, 09 Nov 2007 13:29:52 +0000

Wouldn’t the solar wind just blow the cloud away? After all, that’s what happens to the gas from comets…

By: James

James — Fri, 09 Nov 2007 13:26:34 +0000

Isn’t the Earth presently passing through passing through a Local Interstellar Cloud (LIC) which is flowing away from the Scorpius-Centaurus Association of young stars?
See http://antwrp.gsfc.nasa.gov/apod/ap000412.html

By: Jacco

Jacco — Fri, 09 Nov 2007 10:16:57 +0000

But then, some clouds may be intelligent and come straight for us…

http://en.wikipedia.org/wiki/The_Black_Cloud

By: forrest noble

forrest noble — Fri, 09 Nov 2007 07:09:14 +0000

200 million years is a very long time for humanity. By then, if our species still exists, I believe we will have planet hopped, star hopped, and also would have the ability to very slowly move our planet’s distance in or out from the sun as needed.

http://www.space.com/scienceastronomy/planetearth/earth_move_010207.html

By: Aristotle Pagaltzis

Aristotle Pagaltzis — Fri, 09 Nov 2007 06:19:02 +0000

Phil,

I have to chime in with the others here: to my knowledge, the Sun is at an orbit where it co-rotates with the spiral arm system (or nearly).

Further, I have heard that if Earth had ever entered a molecular cloud, we would find evidence of it in the sediments (though it was not mentioned what kind), and that we have not to this day found such evidence, which, along with the co-rotation fact, suggests that the Sun has actually never flown through a molecular cloud, ever.

As for crossing the spiral arms, thereâ€™s another, greater hazard than molecular clouds there: the presence of molecular clouds implies star-forming regions, which implies young stars, which implies the presence of massive stars that havenâ€™t yet, but may be about to, go bang in a supernova.

So you donâ€™t want to get close to the arms.

Which makes it all the more salient that purportedly we have hints that the Sun indeed never has.

By: Acleron

Acleron — Fri, 09 Nov 2007 04:04:38 +0000

If you could track back in time as well, do any of the extinction periods on earth correlate with interaction with excess particle density? I’ve read this as a cause but wonder if there is any better data to help or deny the hypothesis.

By: John Foudy

John Foudy — Fri, 09 Nov 2007 03:02:30 +0000

There are plenty of species alive today that are more intelligent than our ancestors (whatever they were) were 40 million years ago- that means plenty of time for us to go and for some random species slip into a sex-selection feedback loop that increases brain size

By: Crux Australis

Crux Australis — Fri, 09 Nov 2007 02:06:50 +0000

Aren’t the arms pressure waves that travel backwards relative to the orbital motion of the stars? So it would actually take us a little less than 10 million years?

By: Shannon

Shannon — Fri, 09 Nov 2007 01:34:34 +0000

Wow. That 200 million years number is pretty depressing. I too was hoping to be dug up by future civilizations.

By: The Bad Astronomer

The Bad Astronomer — Fri, 09 Nov 2007 00:16:40 +0000

Molecular clouds have H2 and lots of dust. The densities can be quite high, as much as 10^6 particles per cc.

That Neil Guy: yeah, I have a copy on my desk! I’ll be reading it soon. My book will be submitted to my editor before I can read Asimov’s though.

By: That Neil Guy

That Neil Guy — Fri, 09 Nov 2007 00:14:46 +0000

Phil–

Have you looked through Isaac Asimov’s A Choice of Catastrophes, which (from what you’ve described) covers similar ground to your book?

Just curious!

By: Bryan

Bryan — Thu, 08 Nov 2007 23:06:58 +0000

The sun’s temperature gradually increasing doesn’t seem like a huge issue, since it seems like it’s slow enough that life would simply adapt, as it always has. Also, though, the sun is losing mass through the solar wind. So we’re probably very, very slowly moving away from the sun. I wonder how much further out we’ll be in a few billion years…

By: Kira

Kira — Thu, 08 Nov 2007 22:50:43 +0000

Perhaps I’m wrong here, but I thought molecular clouds were composed of molecular hydrogen, not dust.

By: Darth Curt

Darth Curt — Thu, 08 Nov 2007 22:30:10 +0000

So what you’re say Phil, is that we’ve got some time to kill. Figuratively speaking of course. Very cool Galaxy pic… I always thought we were in the Western Arm… perhaps I’m just remembering that from “Guide to the Galaxy” (The novel, not the radio play, or (ech) movie)

By: Daniel

Daniel — Thu, 08 Nov 2007 22:12:31 +0000

I have to say, that I could not agree with you in 100% regarding nnial 2007 – salvatore iaconesi – del.icio.us poetry, but it’s just my opinion, which could be wrong

By: Mark Martin

Mark Martin — Thu, 08 Nov 2007 21:17:33 +0000

According to Fred Hoyle, those black clouds are intelligent beings, but largely oblivious to the consequences of their transits through the varied planetary systems.