Janus

Even if were possible to point the Hubble telescope at the Moon, it could not resolve anything smaller than ~100m across. The energy of this impact would not make a crater anywhere near that size. The Lunar Reconnaissance orbiter could likely detect it, but it is on a prescribed polar orbit, which may have already mapped that region. If not, we would have to wait until it map the impact point and hope to recognize what would be a fresh crater.

That would put the impact at about the equivalent of ~1/3 of a kiloton. This is roughly 1/40 as much as the bomb dropped on Hiroshima, or 30 times greater than the GBU-43/B "Mother of all bombs", the most powerful non-nuclear weapon in US arsenal.

An eclipse will not cause the temperature to suddenly drop that much that fast. The reason the surface reaches those extremes at day and at night is that it is being slowly warmed by the sun for ~14.5 days and then allowed to slowly cool for ~14.5 days. An eclipse blocks the solar radiation for a bit, but the surface is still holding on to the heat that had built up in it up up til that time. It can radiate that heat away only so fast, and you are not going to see a fast drop in temp of any great degree.

This was an issue faced by the Shuttle astronauts when doing EVAs. The shuttle was kept at at a standard pressure gas mixture, but the suits were pure oxygen at 4.1 psi. So in order to prepare for an EVA, an astronaut had to wash out the nitrogen in their blood by breathing in pure oxygen via a face mask first. This meant a 2 1/2 prep time before being able to do an EVA.

The "Thou shalt not kill" commandment in the Bible basically refers to unlawful killing or killing of the innocent. Thus it has a "built-in" loop-hole. All that has to be done to believe that the killing is justified, as in with an enemy combatant, or that the person is guilty of some crime worthy of death (and the type of crime that fits this has covered a broad range in the past.) The problem with war is that it is so easy to convince yourself that it is justified.( Those people hold land or resources that are rightfully ours and won't be reasonable and give it to us.) And in many instances, it isn't a matter of a loop-hole in your religion, as it is actually using your religion to justify the war.

If I plug the equation into my calculator as written, I get an answer of 0, as 0.5/1.4*1.38e-23*300 = 1.479e-21 and my when my calculator tries to raise e to this power, the answer requires more accuracy than the calculator can handle, so it rounds it down to 1 and then you are subtracting 1 from this. However, I can get an answer when I use the calculator on my PC, as it carries out answers to many more decimal places. If However, you meant to write 0.5/(1.4*1.38e23*300), then then answer to this is 8.63e19, and trying to raise e to this power will produce an overflow error as most calculators can't handle numbers that large They generally have to be smaller than 10100, and anything much larger than e230 will produce an overflow error

Harald explained this in an earlier thread: He mistakenly thought that G was the equivalent of g*m. He also though that m in this equation was the combined mass. So he substituted 9.81 N/kg * (70kg+80kg) for G in the gravitational force equation. (9.81N/kg = 9.81m/s2 )

Second generation " late-born" here. Grand dad was a bit shy of 54 when Dad was born, and Dad was just a few weeks short of 50 when I was born. Don't know what kind of formal education my Grandfather had, but Dad was pulled out of school after the 8th grade in order to help with the family farm.

If you read the essay from which this quote is taken, It seems to be equating religion with "curiosity" or the drive to answer questions. In this, religion was man's first attempt to deal with this curiosity, so there is some connection between the two. Science is the tool by which we examine the world around us. Thus without the driving curiosity that drove us to invent religions, the tools do don't do us much good, and without the tools to properly attack the questions, curiosity by itself leads to no answers. The bone I would have to pick with this quote is his even using the word "religion", Religion is a result of our curiosity, not its source. You could just replace "religion" with "curiosity" and be closer to the truth. The other issue here is putting too much stock in the words of someone when speaking outside of their area of expertise. There is a quote from a book by Heinlein that goes: “Expertise in one field does not carry over into other fields. But experts often think so. The narrower their field of knowledge the more likely they are to think so.”

Gravitational waves are not what mediate gravitational force. A non accelerated mass has a gravitational field and will attract another mass without producing any gravitational waves nor are gravitational waves required for this attraction . Gravitational waves are produced by accelerating a mass and are are a separate effect than gravitational force. Neither do they add to the gravitational attraction of the mass. An asymmetry in a rotating system of masses will produce gravitational waves, but this is not the same as producing gravity.

Even Einstein's intuition led him astray from time to time. He was never happy with some of the aspects of Quantum Mechanics, his intuition told him that the universe just couldn't work that way. He even came up with some thought experiments that he felt showed that QM could produce results that didn't make sense. But when actual experiments based on those thought experiments were performed, the results that Einstein thought didn't make sense turned out to be the actual way things worked.

The Earth's axial tilt varies between 22.1 and 24.5 degree over a 41,000 yr cycle. While this does have an effect on the seasons to some degree, it doesn't on the overall habitability of the Earth.

I had a boss that was the epitome of that. Was so concerned with the prevention of theft that it was almost an obsession. In the end, it turned out that he was misusing funds for personal use.

You understand equation (3) by grasping that 'a' is a value that itself depends on "r". a varies in inverse proportion to r^2, and thus a^2 varies in inverse proportion to r^4. Thus if r doubles, r^2 increases by a factor of 4, but a^2 reduces to 1/16 its value. 4*1/16 = 1/4 and the net value of F has decreased by a factor of 1/4 or 1/r^2. The equation is misleading because it contains a variable which is not independent of another variable in the equation.

Darcy's Law deals with pressure differences across a permeable membrane , in the absence of gravitational forces. But is not the case between heart and feet. Gravity is pulling down on the blood. Blood flowing to the feet is aided by gravity to overcome the pressure difference, while blood going the other way fights gravity which cancels out the tendency for flow from hgh to low pressure. Overall, it's a wash, and you don't have any restriction on circulation between heart and feet. Besides, blood flow is pumped through the body by increasing the systolic pressure above the mean. The difference between mean and systolic pressure ( the pressure generated by the heart to push the blood) is greater than the difference between blood pressure in the feet vs the mean.

You have to use integral calculus to account for the fact that the force, and thus the acceleration, changes as the distance decreases.

There's an equation that will give you the exact answer. it is [latex] T = \frac{\cos ^{-1} \sqrt{\frac{x}{r}}+\sqrt {\frac{x}{r} \left ( 1- \frac{x}{r} \right )} }{ \sqrt {2G (m_1+m_2)}} r^{\frac{3}{2}}[/latex] Here r is the distance between the center of the balls at the start and x the distance between the centers when they collide (2 times the radius of the balls themselves) Using this method, I get an answer of ~2.9 days.

Both electromagnetic waves and gravitational waves (the aspect of gravity that travels at c) are massless entities, and as such are required to travel at c, the invariant speed of the universe. When neutrinos were first proposed and and later discovered, they also were assumed to be massless and thus were expected to travel at c. This is a consequence of Relativity.

What exactly does "fashion sense" even mean? If it were a real thing then the same type of dress would always be "in fashion". But it isn't; What was in fashion 20 years ago would be considered going against "fashion sense" today. So I guess fashion sense is just the ability to see what everyone else is wearing and then copy it.

I Think that it would be well served if you gave your thoughts on the matter and what your reasoning is for it. You went to the trouble of giving the distance between the walls and the activation period for the laser, so I 'm assuming that you think this is important to the answer. Assuming that the whole set up isn't under some extreme acceleration which either severely Doppler shifts the laser or causes its path to bend enough that it hits one of the other surfaces in the room rather than the one opposite it, There is no reason for the laser not to strike the sensitive wall.

Right, he is saying that the speed of light in both directions is the same with respect to any inertial frame as measured from that frame. So in the following example we have two observers. One standing along the tracks and the other traveling along the tracks in a railway car. Two flashes are emitted from two points along the tracks that are equal distance from the track observer. the light from these flashes arrive at the midpoint observer at the same moment as the railway observer is passing him. Thus both observers detect the light from the flashes at the same time. Like this: For the midpoint observer ( or anyone at rest with respect to the tracks) these flashes were emitted simultaneously, as shown by the expanding circles: However, for the railway car observer, events have to occur differently. He still detects the light from both flashes simultaneously, and they arrive when he is adjacent to the track observer. But unlike the track observer he has not remained halfway between the emission points the entire time. He is not an equal distance from the emission points when either of the flashes was emitted. But he must also measure the speed of light for each of the flashes as being the same relative to himself. But since the distances each of these flashes travel relative to him are not the same, in order for the light of the flashes to reach him simultaneously, they must have left at different times. And the sequence of the events for him occur like this: For the track observer, the flashes are emitted simultaneously, but for the railway observer they are not. This is the relativity of simultaneity: Events that are simultaneous in one inertial frame are not so according to another which in relative motion with respect to the first frame.

No. You have three clocks, A, B and C all at rest with respect to each other. For this example we will put them in a straight line, with B between A and and twice as far from C as it is A. When Clock B reads 12:00 it sends a light flash towards both A and C and then waits for the flash to reflect back to, and when each reflection returns, it records the reading it sees on each of the other clocks when its flash returns. So if the flash from clock A returns when clock B reads 2:00, B knows that clock A is 1 light hr away. And if the accompanying image of Clock A shows 1:00, Clock B knows that that image left 1 hr ago, clock A has advanced 1 hr in that time and at at the moment that B sees the returning flash reads 2:00. Thus clock A is in sync with clock B. Further, the flash from clock C returns when clock B reads 4:00, meaning clock C is 2 light hrs away. If the accompanying image of Clock C reads 2:00, Clock B knows that it left 2 hrs ago, Clock C has advanced 2 hrs since then, reads 4:00 at the moment B sees the flash and is in sync with clock B. It also knows that Clock A has also advanced to read 4:00, so all three clocks are in sync. While it is convenient to use equally spaced clocks to determine simultaneity, as it removes the need to determine the distance between clocks, it is not a requirement for determining simultaneity.

No. If you look at the standard time dilation equation: t0 =tf(1-2GM/Rc2)1/2 One thing stands out. It is that 2GM/R also appears in the escape velocity equation: Ve= (2GM/R)1/2 and so, 2GM/R = Ve2 Ergo, we could rewrite the gravitational time dilation equation as: t0 =tf(1-Ve2/c2)1/2 So what we need to do is substitute the escape velocity from the center of the Earth for Ve Escape velocity is reached when the sum of the kinetic energy and gravitational potential energy equal zero. Using specific energies: v2/2-3GM/2R = 0 v2/2 = 3GM/2R v2 = 3GM/R Thus: t0 =tf(1-3GM/Rc2)1/2

Even if we use the fastest estimated rotation rate and the longest estimated length, you only get the equivalent of ~4/1,000,000 of a g at the ends.

I'm aware of that. I was addressing the fact that coffesippin seemed to think that we had actually determined that the object was only 1mm thick and from that hypothesized that it could be an alien craft. Whereas the reasoning goes " If we assume that the accelerations are due to it being some type of light sail, then the object would need to be very thin for that assumption to hold."