Greg H.

So, just for fun. I play Eve Online - earlier this year, they had a live event that resulted in a Leviathan-class Titan plowing into a planet from orbit. According to the game lore, very little damage was sustained on the planet - I'm just trying to find out how much impact energy such a collision would actually have. For this purpose, I am assuming the planet itself is roughly equivalent to the Earth in terms of size, density, and chemical composition. Ship Stats: [math]Mass= 2,430,000,000 kg[/math] [math]Volume= 132,500,000 g/cm^3[/math] Given that the ship was in orbit around the planet at the time, and was subsequently forced to crash, I'll assume the initial velocity was the orbital velocity. In order to calculate the orbital velocity we can set the centripetal force and the gravitational force equations equal to each other, and solve for the velocity in m/s [math] \frac{mv_o^2}{r} = G\frac{Mm}{r^2} [/math] Where: [math]m[/math] = Mass of the ship [math]v_o[/math] = orbital velocity [math]r[/math] = radius of the orbit [math]G[/math] = Gravitational constant [math]M[/math] = Mass of the planet Solving for the velocity gives us the equation: [math] v_o = \sqrt{G\frac{M}{r}}[/math] I had to make some assumptions about the orbital radius, but since the lore tells us that these ships cannot orbit too close to a planet's surface, I chose to use a high earth orbit for the orbital radius. Setting [math] r = 101,000km[/math] gives us a final equation of [math] v_o^2 = \frac{6.67384\times10^{-11}m^3}{kgs^2}\frac{5.97219 \times 10^{24} kg}{101\times10^6 m}[/math] [math] v_o^2 = \frac{(5.97219 \times 10^{24}) (6.67384\times10^{-11})}{101\times10^6 }\frac{m^2}{s^2}[/math] [math] v_o^2 = 3,946,281.2386 \frac{m^2}{s^2}[/math] [math] v_o = 1,986.5 m/s [/math] which seems fair, given the orbital velocity of satellites at that altititude. (continued...) So my first question is: is it fair to use the orbital velocity or do we need to calculate an actual impact velocity somehow, and if so, how would we go about doing that?

This was actually the premise behind the time travel in the TV show Terra Nova.

I can understand confusion - but this was so far off, I'd say it stems more from a complete lack of understanding of the material than any confusion. One day of travel at the speed of light is one light day, which is roughly 173 AU. Relatively speaking, in terms of crossing the galaxy, you haven't even left the driveway yet.

[math]\alpha\,\beta\,\gamma\,\delta[/math]

@uncool - Sorry, I didn't mean to down vote you. Got click happy. My apologies. @PG - There is absolutely no observational evidence to back up the effects that you claim have happened. An anecdote from a religious text not withstanding, when your view of the world clashes with reality, it is not reality that is wrong. Also, by definition, the a light year is the amount of distance light travels in one year. You cannot, by definition, travel 110 light years in 83 years at the speed of light.

It doesn't even come close to satisfying the requirement for evidence. This entire thread is word salad.

Ahh. That's the distinction. An LFTR is a molten salt reactor, but not all molten salt reactors are LFTR's. Thank you for the correction - sometimes I get a little blinkered in a discussion.

My point was that, in the context of the original post, the idea that they had the same initial KE is dependent on a lot more than them both having been shot once. Although as swansont points out, the initial KE is irrelevant anyway, since it's not conserved in this type of collision. What matters is the initial momentum (though I think my point that "one gunshot" being an invalid measure of the force applied to the block is still relevant).

I haven't watched the videos, but you would also need to account for manufacturing disparities in the bullets. Even bullets of the same caliber can have varying weights and load amounts, which will result in varying amount of kinetic energy on impact. You would actually need to weigh each of the bullets (sans powder and cartridge) and get an accurate measure of the speed of the projectile as it impacted the block in order to accurately estimate the amount of kinetic energy imparted to each block.

If you want to be technical, all orbits are around a common center of mass. It's just that when one object grossly out masses the other, the center of mass tends to be inside the larger object. As for your question, I don't know of any non-star objects more massive than a star except for black holes, regardless of their location.

Them being locked does not prevent them from being read.

More so, in my opinion. The CIA, at least, can be proven to exist, regardless of their impact (or lack thereof) on my medical records. I hope I wasn't conveying the idea of having some kind of proof of God. If so, then I apologize - that was certainly not my intention.

This is the problem I would see with the idea. From everything I know about Astonomy and astrophysics, the lighter object always orbits the heavier one. As Swansont says, I don't see how you would get a more massive object than a star without it also being a star. I don't think that would work, simply because the density of the "more massive" object isn't high enough. Remember, you can calculate gravity by way of density using the proper equation, and if the density of the object drops, so does the gravitational pull it can exert. Nebulae, despite their impressive size, are not very dense at all. I'm not sure you'd get noticeable pull from it.

What part of "remain the only two molten salt reactors ever operated" equates to "they were never run"? So yes, two liquid floride fuel salt based reactors were operated as early as the 1950s and in the latter half of the 1960s. They were never run commercially, but they did operate.

I'm not trying to get scientific evidence about the existence of God. Mostly because it doesn't exist - which is how we get back to faith. While that's certainly possible, the principle of Occam's Razor leads me to suspect it's not the case. And my skepticism on that claim is justifiably high.

That leads me to add a new factor to my Skepticism equation. Call it the "Outlandishness" factor.

Let me clarify something based on the responses I got. When I say "a number of people telling me the same thing" I do not simply mean they're wandering around spouting anything at all. They need to have something to back up the claim they're making - and to clarify even further, it needs to be something tangible that I can then take to someone else and say "Hey, what do you think of this?" The doctor, in my example, would use CT Scans, MRI's, etc, which I could take the results of to another doctor and say, "So, is that an aneurysm?" My previous example could probably best be summarized by saying that the level of my skepticism is inversely proportional to the quanity and the square of the quality of the evidence supporting it. [math]S_{me} = O \times \frac{1}{Q_1 \times Q_2^2}[/math] Where: Q1 = quantity, Q2 = quality and O is the outlandishness of the claim. God spoke to you? Great! He's never even sent me a Get Well Soon card. More importantly - how do you know it's God? There's no evidence that it actually is God speaking to you - for all we know, everyone that's heard the voice of God is really just receiving signals from an NSA satellite and should probably invest in a quantity of tin foil. Edited to add a new factor: outlandishness.

While I'm not trying to speak for doG, we all believe things because we've been told by someone else.The difference is, I choose to only believe stuff that could be verified independently. Let's face it, I have to take my doctor's word for it when he says I have an aneurysm - I'm not a medical professional, so I depend on him to know his stuff. However, I could, if I so chose, go ask another medical professional about it. And another. And another. If they all start telling me the same thing, I find that the propensity of the evidence lends credence to the claim. Faith, on the other hand, does not provide evidence. By definition, it demands belief without or in spite of evidence or support. On the other hand, I don't believe that people who believe in religion are "broken" necessarily. They're largely harmless in small numbers - it's only when they gather in large groups and try and use their influence to affect my life that I get irritated. Having faith isn't a problem. Using it as a critical thinking tool may be a problem, depending on the issue at hand.

Actually the universe makes a great deal of sense. It just isn't very intuitive beyond our every day experience. First you complain that the universe doesn't make sense, then you complain that it doesn't make even less sense?

On behalf of the American people, I would like to express my sincerest apologies for the corruption of plain speech and the joy of language over the last hundred (or more) years. It really wasn't our fault. I blame the civil legal system and that atrocity known as political correctness.

That's the point of the self-consistency principle: You cannot make changes to the past - you simply become part of the narrative resulting in the same outcome. You turn the ship, and it rams into another part of the iceberg. You stop the ship, and the iceberg rams the ship. Or you inadvertently distract the crew running around shouting "Beware the iceberg" and they ram the berg because they were too busy dealing with you. You can read more at Novikov Self-Consistency Principle

I am going to put this as absolutely simply as I can. You have made the claim that, contrary to the laws of physics as we understand them, our Sun is somehow fusing Silicon into Iron, despite being far too small to actually do so. Do you have any evidence or any mathematical model (even one you can link to from someone else) that supports this claim? I'm not saying it has to be right - but at this point in the discussion you need something aside from "Because that's what I think" as a response, or we're done here.

Close them both, for that matter.

I was unaware that asking for evidence to back up a claim about science (especially one that deviates significantly from accepted theory) was somehow attacking you or anyone else. How do scientists get through their days with all of these "attacks" without succumbing to the constant barrage and running off to hide. Oh, right. They provide evidence. Or at least a mathematical model that supports their claims. You've provided neither. You've made claims that fly in the face of accepted stellar theories and provided not a shred of either evidence or math to back them up. When asked to do so, you simply wave your hands like a magician while screaming "I'm being oppressed! I'm being oppressed!" in a vain attempt to evoke some kind of sympathy to a plight for which you have only yourself to blame. I'll (vainly) ask you one last time. Kindly provide some kind - any kind - of evidence or mathematical support for your claims. It doesn't even have to be your own work. A journal article - a random letter from a magazine. Something a kid scribbled on the back of a napkin in crayon which has somehow convinced you that science is wrong and you are right would be more than you have presented so far. My conversation with you so far can be summarized as: "The sun fuses Silicon into Iron in the photosphere!" "No, it doesn't." "Yes it does." "The sun doesn't have enough pressure or temperature to do that." "But it happens anyway." "And your evidence for that is....?" "Stop attacking me!"

What does being a priest and/or a nuclear engineer have to do with anything? I'm not a monkey trainer, but I know that Si -> Fe fusion only happens above a certain temperate and pressure. Since the sun does not contain those pressures or temperatures anywhere inside it, including in the core, it is therefore physically impossible for Si -> Fe fusion to take place inside the sun. I am going to move that the moderators lock this thread unless you can actually come up with something besides hand waving to support your idea. In short, provide some evidence for your position, or please stop trying to defend it.