7 minutes of terror tomorrow night

[Ned]

Here is some photos from the MRO of Curiosity with the parachute deployed and the heat shield still falling.

 

[taoshum]

Simple answer - radio waves are just a lower frequency version of light waves.  They leave the transmitting antenna at that speed (the speed of light), and when they get to the receiver whatever is not absorbed by the antenna just keeps on going until it hits something else or fades out.

Like waves generated by dropping a rock in a pond, radio waves get weaker as they travel away from the source, and eventually become weak enough that they're no longer distinguishable from the background noise.

If you fired up a LARGE light on Mars, those light waves would also leave the light bulb at 186,000 miles per second, travel at that speed and take the same 14 minutes to be visible on Earth.

I sorta understand the electromagnetic spectrum and isotropic attenuation but what I've never understood is how the radiation (regardless of the frequency) which did not exist prior to the application of power(flip the switch NASA), goes from zero to full speed instantly, at least in a vacuum.  It's probably wrapped inside quantum mechanics or something that explains why when a mirror or an antenna reflects something travelling 186,000 miles/second, even with incredible intensity, does not feel any force... since I guess it has no mass being either a photon or a wave ...  Nonetheless, the RF can cook food as it flies across the space in a microwave oven, LOL, 'cause I guess it slows down going through the chicken.  Always seem to me that if the chicken can take heat out of the RF, there oughta be some finite time required to get from zero to full speed but I guess there is not. 

The analogy with waves in water kinda breaks down since it takes major forces to reflect water waves, like in the ocean.  It does illustrate geometric spreading though.

Maybe with some of these new discoveries in atomic physics, we will find a way to break the speed of light barrier, LOL.  Then we could see everything in real time... then, of course, we'd event filters instead of frequency filters and tuners.

Be like Bolt and go fast.

 

[Lou Schneider]

what I've never understood is how the radiation (regardless of the frequency) which did not exist prior to the application of power(flip the switch NASA), goes from zero to full speed instantly, at least in a vacuum.

Light only travels at one speed - it can't slow down or speed up unless it's affected by the medium it's passing through. Same with other frequencies in the electromagnetic spectrum.  You're not accelerating mass, just impulses.  I'm not a physicist, and one could probably explain it much better, but it's sort of like the desk toy with 6 metal balls suspended and touching each other.  When a ball strikes against one end of the string of balls, the ball at the other end flies away almost instantaneously and the balls in between barely move at all.

Nonetheless, the RF can cook food as it flies across the space in a microwave oven, LOL, 'cause I guess it slows down going through the chicken.  Always seem to me that if the chicken can take heat out of the RF, there oughta be some finite time required to get from zero to full speed but I guess there is not.

Actually, it's one specific frequency that heats the chicken - RF at the resonant frequency of water molecules.  What happens is the waves passing through the chicken makes the water molecules vibrate, which creates friction and heat.  Shift the frequency higher or  lower and the heating effect is  much less.

BTW: microwave heating was discovered when a technician was experimenting with one of the new WWII microwave radars and noticed the chocolate bar in his shirt pocket had melted.  He later built a box to contain the energy and cooked up a batch of microwave popcorn to confirm his theory.

 

[ArdraF]

Ned - Check DirecTV channel 346 which is the NASA channel.  I don't know which satellite it uses, but that's what I saw it on.

ArdraF

 

[Ned]

346 is NASA TV but it's no longer on the 101 satellite.  You need an HD antenna to receive it even though it's SD.  It was moved a year or so ago.

 

[Wizard46]

Light only travels at one speed - it can't slow down or speed up unless it's affected by the medium it's passing through. Same with other frequencies in the electromagnetic spectrum.  You're not accelerating mass, just impulses.  I'm not a physicist, and one could probably explain it much better, but it's sort of like the desk toy with 6 metal balls suspended and touching each other.  When a ball strikes against one end of the string of balls, the ball at the other end flies away almost instantaneously and the balls in between barely move at all.

Actually, it's one specific frequency that heats the chicken - RF at the resonant frequency of water molecules.  What happens is the waves passing through the chicken makes the water molecules vibrate, which creates friction and heat.  Shift the frequency higher or  lower and the heating effect is  much less.

BTW: microwave heating was discovered when a technician was experimenting with one of the new WWII microwave radars and noticed the chocolate bar in his shirt pocket had melted.  He later built a box to contain the energy and cooked up a batch of microwave popcorn to confirm his theory.

huh  ??? ??? ???

 

[SeilerBird]

huh  ??? ??? ???

What Lou is saying is that light travels really really fast.

 

[Tin man]

I like the story of the radar tech. Tossing the frog in front of the radar and watching them pop..

In OKC

 

[Lou Schneider]

huh

Too much work and not enough sleep - sorry about that.  I'll go back into my corner now....

 

[Ned]

Lou, you didn't get to the good part, duality