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The (Dysfunctional) Family Channel's version of Chicken Little

If you believe your TV (and who doesn't), then you know there are billions of asteroids roaming around the solar system, all waiting for their chance to impact the Earth and wipe out human civilization. If another movie like the Family Channel's "Doomsday Rock" is produced, then I think the asteroids will be doing us a favor.

For some reason, in recent months there have been more TV shows aired about asteroids than there are actual asteroids. When they stick to documentaries, the shows have in general been pretty good. However, NBC decided to make a fictional account of an asteroid strike in their awful, awful made-for-TV movie "Asteroid", which I cannot say enough bad things about. However, after watching "Doomsday Rock", I can honestly say it makes "Asteroid" look like a work of genius.

Before I get truly started here, please take a look at my web page where I review NBC's stab at astronomy. Many of the points I make here will be similar to (if not exactly equal to) points made there. When I refer to something I said on that page, I'll simply link to it and let you find the reference.

First, a quickie plot review: Connie Sellecca plays an astronomer whose father, Dr. Sorensen (played by William Devane), predicts that (stop me if you've heard this before) an asteroid will hit the Earth, causing fires, making acid rain, wiping out civilization, etc. etc. No one believes him, so he of course takes over a nuclear missile silo in Colorado, from which he can launch a couple of nuclear ICBM's at the incoming asteroid and blow it up. The reason people don't believe him is because all the orbital calculations show the asteroid will miss the Earth. The reason he believes it is because of an Australian aboriginal legend that the Earth will end via a "Demon Rock" near the end of the 20th century. Right. Still following me? So at the last moment he is proved to be correct, nuclear missiles are launched, the asteroid is vaporized seconds before impact, and everyone is happy.

Everyone but me that is. Now obviously from my description this movie was not really meant to be completely accurate, and they, like the movie "Asteroid", were willing to sacrifice a bit of scientific credibility for the plot. However, also like "Asteroid", every bit of astronomy they put in was wrong, and the plot was even worse than "Asteroid"'s. I noticed they had a scientific advisor for the movie, but once again, for reasons known only to The Powers That Be at the Family Channel, they obviously completely ignored his advice. So without further ado, let's list out what Bad Astronomy the movie promulgated (in the following list, I will refer to "Doomsday Rock" as "DR" for simplicity):

In an early scene of "DR", Connie Sellecca is lecturing students about astronomy, and one of them asks her the difference between a black hole and a neutron star. She says (paraphrased) "Take Cygnus X-1. It produces gamma rays. Neutron stars have a magnetic field so intense that gamma rays cannot escape. That's how we know it was a black hole."

It's hard to know where to start on this one. First, the correct stuff: Cygnus X-1 is indeed considered to be a black hole, gamma rays have been detected from it, and neutron stars do have intense magnetic fields. After this, though, the writers became terribly confused. Gamma rays are basically very high energy versions of visible light: both are forms of what we call "electromagnetic radiation". The main difference between gamma rays and visible light is that gamma rays have a lot more energy per photon. However, magnetic fields cannot stop light of any kind. They do affect it in many ways, but "stopping" it is not possible. I think the writers were confusing magnetism with gravity. A strong enough gravity can indeed prevent even light from escaping. What produces a gravity field that strong? A black hole. Ironically, the writers got it exactly backwards. A black hole can actually stop gamma rays, but a neutron star can't!

The reason we see gamma rays (and all other forms of electromagnetic radiation) from black holes at all is because the huge gravity of the black hole only stops radiation very close in. The gravity effects reach out a long way, however, and can affect matter around it, drawing it in. As the matter spirals into the black hole, local effects heat the matter up to incredible temperatures, which in turn makes it emit all sorts of radiation. That's why we think Cygnus X-1 is a black hole. In that scene, they try to establish Sellecca as a brilliant astronomer, but really they accomplished exactly the opposite.

Another point: when being grilled by the FBI, an agent comments that she is overqualified to teach high school astronomy. I personally found that a bit insulting. Teaching is one of the most important aspects of astronomy. You may not need a PhD to teach high school, but they implied that it was beneath her. I believe that teaching astronomy is pretty noble, and anyone who tries to teach it to high school students deserves a medal, not derision.

Dr. Sorensen, after taking over the nuclear missile silo, demands (from the Defense Secretary!) the immediate use of Hubble Space Telescope (HST). He says he has the coordinates and it will only take a few minutes to point it. After his demand is met, he immediately gets live video feed of the asteroid from HST, showing the spinning asteroid clearly.

Another densely-packed example of Bad Astronomy. First, it takes a minimum of two weeks to point HST at a given object. Time is very precious and very judiciously doled out on HST, so the 'scope is scheduled months is advance. It is possible to interrupt the schedule with a priority observation, but it takes about two weeks to fit it in. It is literally impossible to point the 'scope in a matter of minutes without shutting it down.

Second, HST cannot take video. You can take a series of observations if you'd like, and then turn them into a movie, but it takes days, weeks or even months to do so.

Third, and related to the second point, it takes a long time to analyze HST data. Even a team of people can take months just to properly get the data in a form where it can be analyzed, and the analysis can take years. Having a live video feed is ridiculous.

Fourth, since impact was hours away, the asteroid would be moving far too quickly for HST to track it. HST is able to track moving objects like planets, comets, asteroids, etc., but only up to a point. Something moving 50,000 miles per hour and less than a day away would be moving too quickly to track, unless it was headed straight for us. However, in the movie several times, it is stated that the asteroid will miss us by "half a million miles". Therefore it was not headed straight for us and HST couldn't track it.

Fifth (fifth! in one scene!), why use HST at all? Hubble is a great telescope in many ways, but it is not a particularly large one. A bigger, ground-based 'scope would be able to image the asteroid much faster, and they wouldn't have to wait two weeks just to get the observation scheduled! But of course everyone has heard of Hubble, so having him demand it was very dramatic. It was also Bad.

Incidentally, later in the movie Sellecca uses a dinky little 'scope and gets as good data as Sorensen did from HST. Go figure.

In one scene, Sellecca needs to check the asteroid's orbit herself. She flies to the Space Scan Observatory in Virginia to use a telescope there. The telescope is located in a lit room, surrounded by computer monitors.

Of course, there is no "Space Scan" observatory there, but that is a bit of license I will forgive (just like the "National Observatory" in "Asteroid"). But as a veteran of Virginia observing, no one would want to build one there. The weather in Virginia, as well as many Eastern states, is just too cloudy and hazy to allow any kind of observing program to run well. You're much better off in the west, where it's clear more often than not. Also, "DR" made the same mistake about putting a telescope in a lit room that Asteroid made.

Later, Sellecca goes to Puerto Rico to use the Arecibo radio telescope. Calling it the "best radio telescope in the world", she uses it to get more confirmation of the asteroid's orbit.

Arecibo is the biggest single radio telescope in the world, but "best" is a subjective term. You do get higher resolution (that is, the ability to split two extremely close objects) using bigger 'scopes, but the highest resolution obtainable is actually done using an array of telescopes. In the movie (and book) "Contact", the signal from the aliens was detected using the VLA, or Very Large Array, which is a collection of 27 radio telescopes acting in unison. Many other telescopes participate in Very Long Baseline Interferometry (VLBI), where telescopes from all over the world observe the same object. When tied in this way, it's as if you had a single 'scope with the diameter of the Earth!

Another problem is with the way Arecibo works. It is built into ground, instead of having a free-standing dish. This allows for more rigid design, which is a convenient way to make it bigger. However, this design limits the amount of sky the 'scope can see. Basically (the last I heard), it was limited to about +/- 30 degrees from straight up. The asteroid would have to conveniently be coming in from that area, and be up in the sky at that particular time. Yet even more silliness on the writers' part. But then, why use a radio telescope at all? An optical telescope would do a better job and be easier to use. Once again, the writers just wanted a "gee-whiz" scene, despite any footing in reality.

Let's look at the asteroid itself: it's about 10 by 5 by 3 kilometers in size, made almost entirely of iron and moving in at 50,000 miles per hour. It is said that the impact will be like the simultaneous detonation of 30 atomic bombs. Sellecca likens it to "shooting a cantaloupe from 10 yards with a 44 Magnum."

First off, astronomers never use miles. We're metric. However, so many numbers in the movie used non-metric numbers that I will use them too when I make a comparison. Secondly, an impact of an object that size, moving that fast, would be a bit more energetic than 30 atomic bombs. That line made me laugh out loud. That volume, given the density of iron, will have a mass of 1018 grams, or about trillion tons (that's a million million tons).

(Note added March 9, 2003: Well, how silly. I made two mistakes in this page originally. I said the mass was 10 trillion tons, when it's really one trillion. I also said the kinetic energy is 5 x 1030 ergs, when it's really 2.5 x 1030 ergs. I corrected these numbers, and state the errors here to keep me honest! My thanks to Bad Reader John Owens for pointing these out to me.)

Moving at 50,000 mph (or about 2 million centimeters per second) means it has a kinetic energy of 2.5 x 1030 ergs. An erg is teensy unit of energy: one megaton is about 4 x 1022 ergs. But wait! We have a lot of ergs in that asteroid. The kinetic energy of the asteroid is about one hundred million megatons! Considering that a large hydrogen bomb is only a few tens of megatons (the largest ever exploded was less than 60), we see that the writers woefully underestimated the energy of the asteroid. Now, not all of the kinetic energy of the asteroid goes into the impact, but if even 1% of it does, we still have something that dwarfs the nuclear capability of every nation on Earth combined.

However, it is nowhere near enough to actually shatter the Earth. Actually, it's only enough to leave a big crater, but even that crater would only be a few kilometers deep. Using gravitational arguments, it can be shown that it would take about 1040 ergs to shatter the Earth. So that asteroid has less than 1 ten-billionth the energy to do that. The movie certainly played fast and loose with their numbers!

At 50,000 mph, the asteroid is said to be 19 minutes from impact. The next graphic shows the asteroid over the Moon's surface, complete with shadow.

The Moon is 250,000 miles away, or five hours at 50,000 mph. At 19 minutes from impact, the asteroid should only have been about 17,000 miles away. That's closer than geosynchronous satellites!

Shortly before impact, the asteroid collides with a comet, which changes the course of the asteroid, aiming it towards Earth.

Puh-lease! I covered all this in my page about "Asteroid". Basically, the odds of that happening are so remote that you can safely say it will never happen. Also, a comet lacks the energy to change an asteroid's course that dramatically.*

Two nuclear missiles blow up the asteroid.

The volume of that asteroid is 1.5 x 1017 cubic centimeters. Roughly, Mt. Everest is the same size. Now imagine dropping two atomic bombs on Mt. Everest. It would be hurt, but not completely destroyed. That asteroid was made of solid iron. Two atomic bombs would not do a whole lot of damage. Certainly, they wouldn't vaporize it. Anyway, what happened to all the mass of the asteroid after the detonation? The thing blew up seconds before impact, which would have put it practically in the Earth's atmosphere. Even vaporized, all the mass would still be headed toward the Earth, which in turn means all that energy would still be dumped on the Earth. They destroyed the asteroid, but changed nothing. Dumping that much energy into the Earth's atmosphere would cause just as much damage. Some people think even more, since now there is no ground impact, but the energy gets spread out and does more damage over a larger area.

I have lots of minor nitpicks as well:

They launch a missile early on as a bluff. The altimeter shows it rising at about 100 feet a second at best. That's about 100 kilometers an hour, or about as fast as a car on the highway. At that speed, it would take ten minutes just to get out of the lower atmosphere! It would have taken hours to get into orbit.

They say the Pentagon is in Washington DC. It isn't. It's in Arlington, Virginia.

An astronomer mentioned Halley's comet, but pronounced it "Hay-lee". Every astronomer I know pronounces it "Hal-lee", since Halley was British. Also, comets are referred to as "Comet such and such", not "such and such Comet".

Over and over again, Sellecca says that the comet will "split". The astronomy term for that is "calving". Why didn't she ever use it, even when talking to another astronomer?

The Russians launch a missile to help our missile destroy the asteroid. However, the asteroid was so close by then that the Russian missile would never have had time to get all the way over to it, let alone at the same time as the U.S. missile.

During this whole thing, the President never gets involved. The Defense Secretary calls all the shots, including one where she orders an atomic bomb raid on a missile silo inside U.S. boundary. Where was the President?

Yegads. A military advisor to the President pronounced "NASA" as "Nassau". I'd think someone of his authority would know the difference between a multi-billion dollar agency and the capital city of the Commonweath of the Bahamas. At least I never heard the word "nuc-you-ler" during the movie.

Lastly, they keep calling it the "Demon Rock" or "Doomsday Rock". However, it's made of metal. Even the title of the movie is wrong!

All in all, this movie was actually worse than "Asteroid", which I would have thought impossible. They even stole the idea of the comet collision! How low can you stoop? I won't even bother commenting on the quality of the writing (besides the science), the acting, the special effects and the direction. The Family Channel, being a supporter of family values, should also want our families to get an education. I sure did, watching this. I'll never believe there is a lower limit to the quality of made-for-TV movies again.

*Note added June 18, 2018: It was pointed out to me that in this section I had originally used a racially insensitive phrase. I wrote this many years ago, and I don't know what I was thinking when I did this, but clearly it was inappropriate. I apologize sincerely for that, and I've removed that content.

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