MovieChat Forums > Impact (2009) Discussion > Did they mean Neutron Star?

Did they mean Neutron Star?

posted 15 years ago by rjcarr
18 replies | jump to latest

I don't think the writers bothered to research what a brown dwarf is. A brown dwarf is simply a star that didn't quite make "star" status. Shrink our sun or enlarge jupiter and you have a brown dwarf. AFAIK, there is nothing particularly special about the density of a brown dwarf.

A neutron star, on the other hand, is extremely dense, because it is a star that has (or in the process of) collapsing. This would make a bit more sense, however, it wouldn't just be floating along with a group of meteoroids, either.

[–] FrenchCelt 15 years ago

Yeah, maybe they got confused thinking that a brown dwarf is a darker version of a white dwarf, which is the product of a dead star. However, a neutron star is so dense that a piece of it the size that they found on Earth would have roughly as much mass as the Earth itself, thus the Earth would have been destroyed when it impacted. The chunk that slammed into the moon would have the same mass as basically every planet in the solar system combined, so the moon would have been obliterated even before that chunk got within visual range.

Basically the writers fail at science.

[–] comairmht 15 years ago

A dead star is a black dwarf, which is a whitw dwarf which no longer generates radiation or barely any at all. No black dward exists yet because the time it takes for a white dwarf to become a black dwarf is longer than the calculated age of the Universe. Nice research ABC.

[–] FrenchCelt 15 years ago

White dwarfs are also dead stars. A star is dead once thermonuclear fusion ceases. A black dwarf is the end state of a white dwarf and should be almost undetectable because of the complete lack of radiation, although its gravitational influence will still indicate its presence. But if black holes were hard to detect, black dwarfs will be even worse precisely because we have no idea when the first one will come into existence...the Earth itself will likely be long gone and humanity either evolved into another state or extinct by the time it happens. It might not happen until the so-called heat death of the universe, which is an unimaginable amount of time far into the future.

[–] Katatonia 15 years ago

I was also laughing when they said something like "a dense piece of a brown dwarf crashed into the moon and weighs twice what the earth does!" and acted like it was reality.

Now, I certainly know what a brown dwarf is...and a white dwarf, red dwarf, neutron star, magnetar, black dwarf, quark star, etc. Even your average lay person has probably read a short article about what exactly a brown dwarf is in a magazine before, or seen it explained in a Discovery/History Channel program.

Was this the "actual science" they were screaming about in the "making of" featurette on the DVD?

I mean seriously, a chunk of a neutron star would perhaps be within the real of scientific plausibility.

[–] mcoelenfun 14 years ago

@Katatonia: Red dwarf! ROFLMAO

[–] ragreen259 13 years ago

Wow, French, did you actually take the time to figure all those masses out on paper, or are you just spewing crap and random numbers that you really have no idea about other than "they're big numbers." If so, don't do that, it's a forerunner to abject stupidity.

[–] FrenchCelt 13 years ago

Neutron stars have up to about twice the mass of the sun packed into a diameter of about 14 miles. All the mass of the planets in our solar system combined total out to less than 1% of the sun's mass. From there it's fairly easy to interpolate the estimated masses of the various chunks involved in this movie if they were made of neutron star material. I know my astronomy and double check my facts before posting them. I don't spew crap and random numbers.

In fact, I just looked up a reference to the size of the chunk that hit the moon as being 19 km. long. If so, I have to revise my estimate of its mass even higher, to that of more than the sun itself, not just all the planets in the solar system combined.

[–] jamstar52 12 years ago

The thing about a neutron star is, it's got enough mass to compact the plasma down into neutronium, a cute substance we can only theorise at this point in time. Yes, it's dense, but what makes it dense is gravity. Take away the gravity somehow, and the neutron star will expand again, the neutronium will 'evaporate' back into normal matter.

A 'brown dwarf' is a big ball of gas that just hasn't quite touched off into a star. Again, it's gravity that makes it dense. Take away the gravity and you get a nebula. There's not a lot that's solid in a brown dwarf.

Yes, this is dumbed down considerably, but I didn't feel the need to post 35 pages of math.

[–] mica404 11 years ago

The flaw in this argument is the 'take away the gravity' step.

Put simply its the body's own compressed mass that generates the gravity that holds it together. The only way to reduce the gravity is to reduce the compression, and the only way to reduce the compression is to reduce the gravity......oh.

Thinking about how the neutron star got there highlights the problem, that once a gas cloud starts collapsing you get: Denser gas, so stronger gravity, so the cloud compresses faster, so even stronger gravity and so on. Once started the process just keeps accelerating and inexorably ends up with some kind of star.

There is not a force in the universe that can reverse it. A star, which is about the most powerful object in the universe, simply holds off the gravity. Until it runs out of fuel.

The self generated gravity is why astrophysicists see things like Neutron stars as stable objects

[–] Frumious_Bandersnatch_46 15 years ago

As I've said on other threads,

The amount of real science in this movie isn't enough to make you blink if it were to fly in your eye.

Given a choice between this "science" and Lewis Carroll, I'll follow Alice and her white rabbit any day.

---
All I can say to the writers, director(s) and producer(s) is:
I admire your ability to get paid for this.
---

---
"The time has come," the Walrus said, "To talk of many things,"
Of atoms, stars and nebulæ, of entropy and genes;
And whether one can bend space;
And why the spaceship shrinks.
---

[–] bodryn 15 years ago

Those who liked this series might also like "Plan Nine From Outer Space".

[–] Frumious_Bandersnatch_46 15 years ago

Why not? Neither one has enough real science to activate the blink reflex if it were to fly in your eye.

Classic Science Fiction allowed the writer one departure from known science. All the rest had to be real science and plausible extrapolations of real science and that one allowable departure.

This must have been much too difficult for some TV writers, so they just put words on paper. Any words at all. Understanding was not important as long as the words sounded "scientific". — And they ended up with a story less logical than "Alice in Wonderland".

Imagine:

"The time has come," the Walrus said, "To talk of many things,"
Of atoms, stars and nebulæ, of entropy and genes;
And whether one can bend space;
And why the spaceship shrinks.

Actually, it's more like this:

"Uncle Cosmo, why do they call it a Word Processor?"
"It's really very simple, Skyler. You've seen what food processors do to food?"

---
All I can say to the writer(s), director(s) and producer(s) is:
I admire your ability to get paid for this.
---

[–] bodryn 15 years ago

That's a good one! Reminds me of when Al Capp said "LSD expands the mind like the bomb expanded Hiroshima."

[–] 15 years ago

[deleted]

[–] michaelexarkun 13 years ago

The density of the core of a brown dwarf star (BDS) would still be quite high, so that fragments ejected from the collision of two BDSs may be in the range of density that the film depicted.

I certainly don't think that the filmmakers meant to depict "neutron star" asteroids slamming into the Moon and Earth.

They were far off the mark, however, when they say that an asteroid twice the mass of the Earth collided with the Moon, and have the Moon survive that kind of collision.

[–] Frumious_Bandersnatch_46 13 years ago

The density of the core of a brown dwarf star (BDS) would still be quite high

But would a piece that small still be heavy enough to have the effect described?

If not neutron star material, then how about white dwarf material?
The point made by other posters — and on other threads — was that a Brown Dwarf is a proto-star that never achieved the density necessary to ignite fusion.

I completely concur that anything striking a body the size of a major satellite hard enough to change its orbit would shatter it into rubble. Changing a large body's orbit without shattering it is a matter of gentle force applied over a considerable amount of time.

Another part that had me puzzled was how they expected to "magnetize" the foreign material (whatever it was) by attaching one end of a wire to it. — And just how that was going to lift it off the Moon and return said Moon to its original orbit.

And then there was the two huge pieces (so close together) being described as "in a stable orbit."

---
"The time has come," the Walrus said, "To talk of many things,"
Of atoms, stars and nebulæ, of entropy and genes;
And whether one can bend space;
And why the spaceship shrinks.
---

[–] imdb-15906 11 years ago

Is it racist that the moon was attacked by a BROWN dwarf instead of a WHITE dwarf? Is this some kind of anti-immigration allegory?

[–] Frumious_Bandersnatch_46 11 years ago

You funny guy!

I'm green with envy that I didn't think of it.
At least the Moon wasn't attacked by a Red Giant. Think of the McCarthy-era plot someone could have made of that.

---
"The time has come," the Walrus said,
   "To talk of many things,"
Of atoms, stars and nebulæ,
   Of entropy and genes;
   And whether one can bend space;
   And why the spaceship shrinks.
---