The Leap Second Explained | Space Time | PBS Digital Studios

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1. time is an illusion
2. Thank you for explaining this CORRECTLY! Every other article on the matter says leap seconds are needed because the earth is slowing down. This is WRONG. Even if the earth stopped slowing down right now, we would still have to add leap seconds at the rate of 1 every 1.5 yrs, because the way the second was defined in 1967.
3. one more time, i didn't quite get you
4. I assume the sun would burn Earth before It slowed down enough to matter or else it would have been addressed in the Earth destruction thing? Idk
5. why you speak so fast? Do you really think this is a good idea?
6. why cant we just find the most steady, stable day of the year and leap second every year?
7. Hopefully we won't have to do leap seconds regularly more than once a year at some point in the future, because that would REALLY suck, particularly for programmers.
8. eh... 'scuse me maam. Just one question before I go... Why doesn't the scientific community just re-calibrate the earth-second to match the current state of Earth's rotation and spin instead of inserting leap-seconds to accommodate a two-centuries out-of-date calculation? And therein save Google from having to invent the leap smear?
   
   If I understood the video (I may very well have not), then it sounds like a lot of very smart people have done a lot of very hard work to accommodate a problem that only exists in an imagined disparity between semi-arbitrary definitions of something that is presently measurably different than the figures in use; and that we have no plausible reason to continue using. Am I missing something or are we applying duct tape solutions when we've got replacement parts in the truck?
   
   Presuming I'm not just really confused, it raises a fun question: If we re-calibrate the earth-second to match the current spin and rotation of the Earth around the Sun, how many years would it be before we'd need our next leap-second, or better yet, a leap-second coupled with another re-calibration? I mean, if you're going to bother everyone with a leap-second, you might as well fix the broken timebase too.
9. so the earth spinning is slowing down could we asume it is due to increased total mass of earth is increasing? i mean few centuries ago all the energy that we released from fossile fuels wasnt in the atmosphere
10. so back in the dinosaurs days the day was shorter? cool
11. Please consider referring to "noon" or "12 noon," and "midnight" or "12 midnight," instead of 12am or 12pm.  http://www.nist.gov/pml/div688/times.cfm .  Just for reference, there doesn't seem to be an easy way to find out, as I've done much (Google) searching and reading, but the day would seem to begin (and not end) with midnight.
    
    Earth is slowing down currently, but the standards also allow for removing a leap second.  If somehow Earth were to speed up its rotation, and DUT1 therefore grow in the opposite direction to presently, the correction would be removal.  But at this point, it would seem unlikely.
    
    Another misconception I have heard in popular media is that a leap second occurs multiple times, like daylight saving time to standard time (or vice-versa) transitions, as in, one per timezone.  That's simply not the case; it is inserted (or deleted) once globally, at midnight UTC on either 30-Jun or 31-Dec (so 8pm EDT or 7pm EST for example).
12. I love this channel. It's free of political bullshit and is nothing but objective hypotheses, theories, and law.
13. Through Einstein's work, we discovered that Newton wasn't correct after all.
    
    Now that we have discovered that the speed of light is not constant, should we not question our current understanding of the universe?
14. also look for the following video
    https://www.youtube.com/watch?v=jlTVIMOix3I
15. there is also a picture which depict the concept more clearly but i couldnt upload
    here is the website for any one
    http://www.quora.com/Relativity-physics/How-can-space-time-curvature-be-explained-in-laymans-terms
16. i am afraid you are mistaken look for fymen explanation of space time  
    
    
    Feynman's Explanation
    So now we have a method to determine a curved geometry. 
    
    The problem I find students having with the above example is the misconception that for a flat space to be curved, it then has to be curved into a higher dimension, like our 2D chalkboard curving into a 3D space. Or worse "our 3D space is curved into the 4th dimension which is time" which is wrong on so many levels. Time is curved too, and in fact our Newtonian gravity is basically due to curved time. [1]
    
    So Richard Feynman demonstrates this beautifully by imagining a bug world and measure distances with a metal ruler, as shown:
    
    
    source: Curved space
    
    Now, imagine a hot spot in this bug world and what might happen if the bugs were to measure out distances as normal. They metal rulers would expand in hotter regions compared to cooler regions and consequently they would find that Euclidean geometry is not valid and they live in a somehow curved space.
17. Space can end, anyway you go.
    
    
    
    Space can take a shape.
    
    
    
    Space can move.
18. Loving the series!
    I just finished reading the illustrated Brief History of Time and am on to Universe in a Nutshell; i'm wondering if anyone here could recommend subsequent books I should check out that maintain an accessible-yet-not-too-diluted tone for explaining some hefty physics concepts to a layperson.  Thanks!
19. Am I hallucinating? Because I clearly remember watching a video by Gabe explaining leap seconds as a consequence of a discrepancy between the seasonal cycle and the earth's revolution around the sun. Now, I'm really confused.
20. Isn't the second defined as the time it takes light to travel 299 792 458 metres in a vacuum?