Diet and environmental aspects do have an effect on things like aging and gene expression.

You could go prematurely grey or bald and end up looking quite different to your identical twin if your QoL standard varies a lot.

Its not entirely a non-factor.

Thank you for answering the question.

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Orbital velocity: ~8km/sec
Seconds since original launch date: ~765,849,600
Seconds at observer: ~765,849,600.27268

So to answer your question, the original section of the ISS is about a quarter of a second younger than it would be if the parts had stayed on Earth.

Same with absolute space. If we measure speed relative to something, maybe we should be asking the same for age: "How old relative to whom?"

>GPS satellites have to regularly reset their clocks to stay accurate to earth surface time due to the relativistic time difference between the satellite and the earth surface.

This is not accurate, they use clocks that run ever so slightly slower

Don't know the exact number but roughly the scale. We are talking about a millionths of time going faster, so over 25 years.. maybe a couple seconds or so younger than we give it credit for.

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It would be very easy to tell them apart genetically. The chances of anything close to the same genetics would be astronomically small, something like winning the lottery every day of an 80-year life.

However, they would likely be more similar to each other genetically than a random set of 2 human beings of the same gender and ethnicity.

> Also outside of nature there is the just as important nurture.

I don't think nurture has anything to do with your physical appearance

Are we talking homo sapien? Yes. The number of chromosomes and number of genes (or recombined genes) aren't directly related. By definition, a species will have the same number of chromosomes, 'though gametes obviously have one of a pair and somatic lines both pairs, with the exception of cells that dispense with the nucleus like RBCs and platelets.

If your prof is discussing transposons or miosis (as opposed to mitosis), you might want to ask them for clarification.

A form of this question is asked after virtually every large earthquake that makes the news, so I'm going to keep my answer generic with the futile hope that I can put this in our FAQs and maybe retire this question. To first cover the underlying geology and earthquake behavior, there are specific processes by which one earthquake can trigger others. This is discussed in more detail in one of our FAQs, but in short we can consider either static or dynamic triggering. Static triggering is where the permanent movement of the crust that results from a particular earthquake changes the stress state on neighboring faults pushing some of them closer (or past) failure through stress transfer. Static triggering occurs over a very limited distance (roughly X km away from anywhere along the portion of the fault that ruptures where X is the total length of the original rupture). Dynamic triggering is where passing seismic waves, and the temporary change in stress they induce, causes a portion of a fault to fail. Dynamic triggering can occur over long (i.e., teleseismic) distances, but it tends to mostly be associated with very large magnitude earthquakes as the generative event, is pretty rare, is temporally limited (i.e., we only consider dynamic triggering to be possible over a narrow time window after the original event), and is hard to demonstrate. Given the above, when this question gets asked, i.e., "There was a big earthquake in location X and then there were moderate magnitude earthquakes in distant locations in the days, weeks, or months following, are they related?" there is a vanishingly small probability that one or more of those events may be a dynamically triggered event, but the overwhelmingly vast majority of the time, the answer is firmly and unequivocally, "No, they are not related".

So what's going on and why is this question asked so often? Mostly cognitive biases. Specifically, some mixture of the frequency illusion and the clustering illusion. The frequency illusion (or Baader–Meinhof phenomenon) is basically the tendency for your brain to take note of similar events after you become aware of an event. So, a large magnitude earthquake hits a populated area and makes the news and for some period after that you (and the news media more broadly) take note of other even moderate magnitude events. This also brings in the second bias, i.e., the clustering illusion, or the tendency for us to see patterns in stochastic (random) things. Within this context, it's worth considering just how many earthquakes of a given magnitude there are, e.g., the global statistics from the USGS. You'll notice a rough logarithmic behavior in these, i.e., for M8+ we expect about 1 a year, for M7-7.9 ~15/year, for M6-6.9 ~150/year, for M5-5.9 ~1500/year, and so on. So in a scenario where one of the ~15 7-7.9 events happens in a populated place and you notice a tiny fraction of the hundreds to thousands of 6-6.9 or 5-5.9 magnitude events we expect every year that also occur in a different populated place (i.e., excluding aftershocks from the original event) in the following days/weeks, does that mean anything or imply any linkage? No, almost always, it represents nothing other than you paying attention to a small fraction of events because you are primed to and seeing patterns that aren't there.

What will really bake your noodle is when you understand the question, "how old is the universe?"

Seriously, if there is no uniform time, how old is anything really? Are there some parts of the universe that are trillions of years old, or others that aren't even a second old?

Yes. Any two simultaneous double-stranded breaks have the potential to be stitched together during repair, although translocation events are going to be much much less frequent than the correct recombination (and observed even less frequently than that due to spontaneous death or targeted removal of cells where this occurs). But it is not impossible for the cell to survive and even propagate after such an event.

Here’s a paper discussing the topic: https://www.pnas.org/doi/10.1073/pnas.1410112111

So, is this the answer to OP's question?

(roughly) 8000 nanoseconds * 365 = 2.92 ms per year?

So the oldest part of the ISS is like 0.075 seconds younger?

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I read that if relativity wasn't corrected for, GPS would accumulate an error of 10km per day. Seeing those nanoseconds translated into the functional accuracy we depend upon, really his this home for me.

The earth has the same amount of water it had billions of years ago. All of it has just been constantly recycled back into the atmosphere, then into rivers and oceans as rainfall, then back into the atmosphere, etc. Known as the water cycle.

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