Back from LA with Honorverse move news

Addressing Prolong,

My suggestions goes the another way.

1) Have prolong administered when people are in their 30's 40's for the movie. Use younger actors and use makeup to age them up!. This way if you use the same actors thier natural aging will grow into what has been potrayed already extending the ability to use the actors.

2) Steal from Dr. Who and have prolong be reapplied every so often which has the side effect of changing the appearance of the receipent to some degree. This way you can recast the actors with out too much problem.

namelessfly wrote:You articulated my point far better than I have been doing by asking this rhetorical question.

I believe you will agree that, regardless of the density and the surface area, the spectrum of the radiation of the superheated bomb remnants will be a blackbody spectrum?

A nuclear explosive is not initially an emission of energy as black body radiation.
Most of the energy yield from the bomb is in the form of gamma rays, X Rays and KE of Neutrons and the expanding plasma. Depending on size and geometry, most of the energy from the Gamma Rays, X-rays and Neutrons will not be captured by the expanding plasma cloud to be reradiated as black body radiation.

Hm. My statement is correct, as far as it goes. The superheated bomb remnants do radiate a blackbody spectrum. In fact, the x-rays are part of that. Fission and fusion reactions produce gamma rays, not x-rays. The x-rays are created when the gamma rays heat up the surrounding material (in this case, the bomb) to more than 60 million degrees, at which temperature the peak of the blackbody spectrum is deep in the x-ray range.

But you do have a point about the gamma rays. My calculations assumed that most of the radiant energy ends up in the blackbody radiation. But much of the gamma radiation escapes. I don't see anything in my sources to help figure out how much of the gamma radiation goes into heating the bomb itself.

But I have an idea on how to calculate the energy in the blackbody radiation, completely independently of any other information about the explosion except the temperature. This will go into a new post.

Regardless of the scientific minutia of how much visible-spectrum EM radiation would be emitted by an actual, real life space nuke, film is a visual medium, and therefore we will almost certainly see the missiles explode (and the lasers fire) as if 100% of the radiation produced was visible. If you really need to, handwave it as a high-tech camera filter that displays non-visible light as visible as an aid to mid-fight tactical analysis or some BS like that.

Also, the idea of Abigail looking up at the explosions in the night sky - small, distant flashes of destruction - and expressing her desire to join the Navy is such a powerful scene that I don't think any reasonable viewer could object.

Taurus2 wrote:Regardless of the scientific minutia of how much visible-spectrum EM radiation would be emitted by an actual, real life space nuke, film is a visual medium, and therefore we will almost certainly see the missiles explode (and the lasers fire) as if 100% of the radiation produced was visible. If you really need to, handwave it as a high-tech camera filter that displays non-visible light as visible as an aid to mid-fight tactical analysis or some BS like that.

Also, the idea of Abigail looking up at the explosions in the night sky - small, distant flashes of destruction - and expressing her desire to join the Navy is such a powerful scene that I don't think any reasonable viewer could object.

Exactly. I've stayed out of this "discussion" so far, but there is a phrase that trumps all: artistic license. It's a movie, it's fiction, it's a visual medium, it's an art form. For some things, you need to forget about "reality" and go for simple emotion, and this is one of them.

Thank you.

It has been decades and two, near death episodes since I did anything in plasma physics. My younger son absconded with my text books on fusion reactor physics.

One of the big issues is the effective emissivity of the Plasma cloud. As you pointed out earlier, most emissions from a plasma cloud involve interactions with magnetic fields. The Chromosphere and Corona of a star are far hotter than the photosphere, but they radiate relatively little energy because the effective emissivity is so low.

Whatever the physics, it would be a cool scene to have Abby and her dad watching the Battle through a big telescope. Make the point that it is the. Young, stead holders daughter's telescope and she is the one who knows how to use it plus she us a navy technology buff.

SWM wrote:

namelessfly wrote:You articulated my point far better than I have been doing by asking this rhetorical question.

I believe you will agree that, regardless of the density and the surface area, the spectrum of the radiation of the superheated bomb remnants will be a blackbody spectrum?

A nuclear explosive is not initially an emission of energy as black body radiation.
Most of the energy yield from the bomb is in the form of gamma rays, X Rays and KE of Neutrons and the expanding plasma. Depending on size and geometry, most of the energy from the Gamma Rays, X-rays and Neutrons will not be captured by the expanding plasma cloud to be reradiated as black body radiation.

Hm. My statement is correct, as far as it goes. The superheated bomb remnants do radiate a blackbody spectrum. In fact, the x-rays are part of that. Fission and fusion reactions produce gamma rays, not x-rays. The x-rays are created when the gamma rays heat up the surrounding material (in this case, the bomb) to more than 60 million degrees, at which temperature the peak of the blackbody spectrum is deep in the x-ray range.

But you do have a point about the gamma rays. My calculations assumed that most of the radiant energy ends up in the blackbody radiation. But much of the gamma radiation escapes. I don't see anything in my sources to help figure out how much of the gamma radiation goes into heating the bomb itself.

But I have an idea on how to calculate the energy in the blackbody radiation, completely independently of any other information about the explosion except the temperature. This will go into a new post.

KNick wrote:You have been using a 1Mton explosion for your calculations. Where did you get that figure? I thought the Honorverse missile warheads were bigger than that. How does increasing the output of the warhead increase the visibility of the fireball?

All you more scientific types on here, how close would a 20MT nuke in space have to be to have a physical affect besides EMP and radiation?

SWM wrote:

namelessfly wrote:You articulated my point far better than I have been doing by asking this rhetorical question.

I believe you will agree that, regardless of the density and the surface area, the spectrum of the radiation of the superheated bomb remnants will be a blackbody spectrum?

A nuclear explosive is not initially an emission of energy as black body radiation.
Most of the energy yield from the bomb is in the form of gamma rays, X Rays and KE of Neutrons and the expanding plasma. Depending on size and geometry, most of the energy from the Gamma Rays, X-rays and Neutrons will not be captured by the expanding plasma cloud to be reradiated as black body radiation.

Hm. My statement is correct, as far as it goes. The superheated bomb remnants do radiate a blackbody spectrum. In fact, the x-rays are part of that. Fission and fusion reactions produce gamma rays, not x-rays. The x-rays are created when the gamma rays heat up the surrounding material (in this case, the bomb) to more than 60 million degrees, at which temperature the peak of the blackbody spectrum is deep in the x-ray range.

But you do have a point about the gamma rays. My calculations assumed that most of the radiant energy ends up in the blackbody radiation. But much of the gamma radiation escapes. I don't see anything in my sources to help figure out how much of the gamma radiation goes into heating the bomb itself.

But I have an idea on how to calculate the energy in the blackbody radiation, completely independently of any other information about the explosion except the temperature. This will go into a new post.

Regarding the gamma radiation, the nuclear tests found that between 0.1% and 0.4% of the bombs energy was emitted as gamma radiation. No estimate on the neutron flux was included, but looking up Neutron bombs, the normal flux is about 5% of the energy released, but can be boosted to 50% if it is desirable. I am far from an expert, but I'd think there would be no benefit from a large neutron flux from Honorwerse weapons. Thus your 80% estimate on the electromagnetic radiation seems to hold up.

New calculation, based on thermal energy!

The Masadan base missiles at Blackbird are described as weighing 160 tons, "more than twice as much as her own missiles". So let us assign a mass of 75 tons to Honor's missiles.

We know that a nuclear explosion starts out at 1 microsecond, when the explosion is a few meters across (about the size of the missile), it has a temperature of tens of millions of degrees. And the initial gamma rays and first x-rays have given the entire volume a uniform temperature. So, if the entire missile is raised to the temperature of, say, 20 million degrees, how much thermal energy has been imparted to the missile?

Not knowing the material composition of the missile, we will have to guess at its heat capacity. Typical materials have a heat capacity of 1 Joule per gram per degree K, with a variation of about a factor of 2. The missile is 160,000,000 grams. Heat capacity times temperature times mass equals total thermal energy. That means that the thermal energy of the missile after it has been vaporized to a temperature of 20 million degrees is
3.2e15 Joules.

We have already seen that the temperature drops precipitously. Within 1 millisecond, much more than 99.9% of the thermal energy has been radiated away in blackbody radiation. So if we use 1 millisecond for our time (as I did before), the mean power of the blackbody radiation flash is 3.2e18 Watts. This is close to the total power of the 1 megaton bomb I calculated earlier. Given Namelessfly's point about the escaping gamma radiation, I will assume that this is not a 1 megaton bomb, but a 15 megaton bomb, with plenty of power to raise the temperature of the entire missile to an even 20 million degrees. That means the blackbody radiation is only 5% of the total energy of the explosion.

As before, we will assume that the visible portion of the blackbody radiation is in visible frequencies. This gives a power in the visible spectrum of 3.2e15 Watts. Since this is nearly identical to the values I worked with last time, I will skip the remaining calculations. From Grayson, the explosions will be apparent magnitude 2. This is 3 magnitudes dimmer than I calculated last time a 15 megaton bomb, but still brighter than the stars in Orion's belt and easily visible.

Since this is based entirely on the temperature of the initial fireball (well established in scientific papers) and the mass of the missile, I think this is pretty robust. It is independent of any other features of the explosion.

I should also note that I agree that even if the physics said that the explosions were not visible, it would be reasonable to say they were for the purposes of the movie. I was actually surprised when my first calculations suggested that they really would be visible--I had expected to say it wouldn't be.

Where they get the sidewall penetrators to work against Saladin it says the missiles are 78 tons.