I just wish I had "the eye" Noel. Our first trip to Egypt was with just a small group of friends. And I took some of the best pictures of my life on that trip. How you might ask? Well, one of the ladies in the group was a professional photographer. And, boy, did she have "the eye". So, I just followed her around and took the same shots she did 🙂 . Seriously though, I'm really just not good with a camera - any camera. I've owned more Nikons over the years than I'm willing to admit to. It took me a few years to realize that, while it helps, the best camera in the world will take lousy pictures if the guy handling it doesn't know what he's doing....Doug

If we were still alive in 50 years I don't think we would recognize anything but some of Earth's physical features. We are getting smarter. 

Bill W

On 11/29/2021 at 8:15 PM, qqwertzde said:

if it is moving very fast from the perspective of a person, the muon may live much longer as measured on the person's watch. The muons we detect on Earth are generated in the upper atmosphere ( > 10km) and are moving close to the speed of light. Within a microsecond, they would only be able to cover a few hundred meters, but in our time they live sufficiently long to reach the Earth's surface.

my latest belief is that there is no universal 'spacetime' as I have been thinking.

The person has his spacetime and the muon has its own spacetime and the muon's spacetime is constantly changing until it reaches the point where the person is and then they share the same spacetime.  So the 'few hundred meters' is only the distance travelled by the rules of the person's spacetime but the muon's spacetime(s) cause it to actually cover much more distance.  yes?  no?  pizza?

On 11/29/2021 at 6:39 PM, W2DR said:

 All people are exposed to different things during their lifetime.         

Just don't "expose" yourself to me!  I'll go blind!  😎

1 hour ago, sightseer said:

my latest belief is that there is no universal 'spacetime' as I have been thinking.

The person has his spacetime and the muon has its own spacetime and the muon's spacetime is constantly changing until it reaches the point where the person is and then they share the same spacetime.  So the 'few hundred meters' is only the distance travelled by the rules of the person's spacetime but the muon's spacetime(s) cause it to actually cover much more distance.  yes?  no?  pizza?

Pizza! Definitely! ( https://insidetheperimeter.ca/physics-eating-pizza/ ) 😉

Conventionally, one would think of only one spacetime in which all matter and radiation is moving. However, in quantum physics, there is the many-worlds interpretation, which basically states that (many!) new universes are created each time we observe something. In that sense, everything is attached to many different universes. I am not a fan of that interpretation, but it is a consistent point of view.

As for the muon, one can explain the conundrum of having different times for the person and the muon by taking into account that not only time depends on how fast something is moving ("time dilation"), but also space ("Lorentz-Fitzgerald contraction"). From the point of view of the person, the muon lives longer, so it can travel farther. From the point of the muon, it only lives for a microsecond, but since the Earth's surface is moving towards it, the distance is contracted. Hence, the muon does not live longer, but it has to travel a shorter distance to hit the Earth.

The bottom line is: time and distance are relative in the sense that different observers will measure different values for both. However, the measurements will lead to the same physical conclusions (e.g., that the muon can hit the Earth). Yes, it's complicated 🙂

 

1 hour ago, charliearon said:

Just don't "expose" yourself to me!  I'll go blind!  😎

You have no idea what you'll be missing. Just ask Sandi Lee, or Patti Ann, or Donna Jean...............

Edited December 1, 20214 yr by W2DR

On 11/29/2021 at 1:06 PM, Mace said:

Don't worry, it's as alien to me as it is to you, and I'm still in my 40's but pushing towards 50

You think it's alien to you now? Just wait until you're pushing 80...........Doug

@qqwertzde  thanks for the reply and all attempts to make me understand.  I've encountered the following video which has helped me understand how it is that the speed of light is constant for all observers (meaning that while travelling at half the speed of light, light is still lightspeed faster than you but yet that same light is still travelling at lightspeed to a stationary observer).

This video makes my head explode to some degree -- not due to math or concept but rather due to anyone's insistence that reality is what we say "because...math".  But I'll go with it and keep thinking because its fun.

Note that some of the comments are also helpful.  PBS SpaceTime videos always lose me and Veritasium videos don't quite explain things but this guy seems to break through for me.

 

 

20 hours ago, W2DR said:

Just wait until you're pushing 80...........Doug

 

Pushing 80 lbs in a one arm behind the neck triceps extension is very good. 

Respect! 

💪

I'm lucky if I can hoist 80 lbs with a fork lift. My wife and I work at a local food bank and there's a lady there who routinely lifts 50-60 lb. boxes. And she's 73. Makes me wonder...........

26 minutes ago, W2DR said:

I'm lucky if I can hoist 80 lbs with a fork lift. My wife and I work at a local food bank and there's a lady there who routinely lifts 50-60 lb. boxes. And she's 73. Makes me wonder...........

Oh, Gawd!  Remembering my Navy days....Being an AT-2 (Aviation Electronics tech)  and having to carry 2 AN/ARC-27 UHF radios up 4 sets of ladders from our shop on the flight deck level to the flightdeck during General Quarters, because the EKA-3b Skywarrior carried 2 and both would go belly up during a flight!  Each weighed close to 50 lbs.

Under normal ops, one could ride an elevator up from the hangar deck to the flight deck.  It wasn't really allowed during GQ.

Here's a pic of one: A true vacuum tube beauty!

 

3 hours ago, sightseer said:

@qqwertzde  thanks for the reply and all attempts to make me understand.  I've encountered the following video which has helped me understand how it is that the speed of light is constant for all observers (meaning that while travelling at half the speed of light, light is still lightspeed faster than you but yet that same light is still travelling at lightspeed to a stationary observer).

This video makes my head explode to some degree -- not due to math or concept but rather due to anyone's insistence that reality is what we say "because...math".  But I'll go with it and keep thinking because its fun.

Note that some of the comments are also helpful.  PBS SpaceTime videos always lose me and Veritasium videos don't quite explain things but this guy seems to break through for me.

 

I just had a look at the video. I didn't like his explanations with the angles very much. It is not really wrong, but I am pretty sure many people might get wrong ideas from it. Math is really important to properly understand all of this pretty confusing stuff, but it is not the reason why we think that light travels at the same speed for all observers. The reason is simply because countless experiments have shown that this is actually the case. Math just models these findings very accurately. 

My favourite relativity experiment is the GPS system. The satellites move at several km/s, which is a tiny fraction of the speed of light, but still enough to make their clocks go slower by several nanoseconds every day. Likewise, they are farther away from Earth, so gravity changes their time by a similar amount of time. Only if you take both effects into account will GPS give you your correct location on Earth. If relativity is ignored, your location will be off by a kilometer within a matter of days.

Charlie - Good Lord. Rack-mounted vacuum tube thingies. My first job with the telephone company involved rack-mounted stuff. I was a summer intern with Pacific Telephone (remember them?). My "office" (a small cubicle) was at 140 New Montgomery Street. My job was to develop a routine maintenance plan for something called N1 Carrier. That's one of those things used to transmit telephone calls. The N1 units were vacuum tube, rack-mounted, and the highest one was about 30' above the floor. Fortunately they only weighed about 20 pounds. Climbing those ladders scared me to death. The central office where I developed the plan was up on Pine Street. Maybe you know where that is. I wonder if it's still being used?.....Doug

Edited December 2, 20214 yr by W2DR
kant spel

I knew where Montgomery Street was Doug.  Never heard of New Montgomery Street.

When you've been away from your home town for a decade or more it gets (WNA) off and changes things to confuse you if you ever go back.  I know where Pine Street is too.

Noel

Edited December 2, 20214 yr by birdguy

2 hours ago, W2DR said:

I'm lucky if I can hoist 80 lbs with a fork lift. My wife and I work at a local food bank and there's a lady there who routinely lifts 50-60 lb. boxes. And she's 73. Makes me wonder...........

 

Roids! 

 

Edit: I mean steroids not haemorrhoids. All though she probs has those too. 

Edited December 2, 20214 yr by martin-w