Ask any question you want about Physics

a reply to: Arbitrageur

Not everything bearden says is crazy, just a lot of it.



Wait what beardens a crank?!? Does that mean I have to take down all my bearden posters in my bedroom?

(Cuts to bassplyr trying to sell heart shaped bearden posters at this weekends garage sale)

a reply to: BASSPLYR

Lol

a reply to: Arbitrageur

I have a question to do less with physics more with astro-physics and the universe! would this be the right place for that?

a reply to: BASSPLYR

I'm gonna miss you...

originally posted by: BASSPLYR
a reply to: Arbitrageur

Not everything bearden says is crazy, just a lot of it.

That's the way cranks operate, they throw in something that's true once in a while just to keep people confused.

originally posted by: combatmaster
a reply to: Arbitrageur

I have a question to do less with physics more with astro-physics and the universe! would this be the right place for that?

Any kind of physics is on topic here, ask away. (But only certain kinds of cosmology, not this kind):

a reply to: Arbitrageur

haha... nice you frog !
you must be one if you see photons as you said.
*kidding

so I assume you telepathically communicated with a frog and it told you that ??

reincarnation ?? is this scientific "truth" like a black hole ??

originally posted by: KrzYma
reincarnation ?? is this scientific "truth" like a black hole ??

Frogs really can see photons, while my comment about reincarnation was meant to be an entertaining prod to get you to think outside the limitations of your own sensory equipment to figure out what's going on in the universe:

The seeing power of frogs: Frogs can detect single photons of light

A quantum light source demonstrates that light-sensitive cells in frog eyes can detect single photons. Miniature light detectors in frog eyes known as retinal rod cells are directly and unambiguously shown to detect single photons of light

You can see photons too but not individual photons. It takes multiple photons to trigger the receptors in human eyes.

My question is this why is our known universe mostly matter, what happened to all the anti-matter.

This question is based on the assumption that at the start of the universe matter/anti-matter ratio was 50/50.

originally posted by: bhaal
My question is this why is our known universe mostly matter, what happened to all the anti-matter.

This question is based on the assumption that at the start of the universe matter/anti-matter ratio was 50/50.

We don't know the answer, it's an unsolved problem.

One idea is there could be some kind of slight asymmetry between matter and anti-matter but we haven't found it yet and we're still trying to figure out what it is. There are other ideas too.

a reply to: Arbitrageur

theoretically speaking, if you could somehow transport a high powered telescope and human being to a point in the universe that light from earth has not yet reached.... technically you would be able to see the history of earth (e.g. the light that has left earth 2000 years ago would be seen by the telescope hence you would see 2000 years in the past).

similar to the way we see distant stars....

now, i know this presents many technical difficulties probably damn near impossible to achieve, but im not talking about the feasibility of this, theoretically i want to know if im wrong, if my perception of the way light works over vast distances is somewhat on track with reality!

Thanks for taking the time to answer this, its been on my mind for some time!

a reply to: Arbitrageur
so.. rod cell from a frog's eye react to EM radiation at a wavelength of 532 nano-meters.
where is the photon ???

OK, another example, how does the number 2 looks like ??
not the shape we draw on paper or on the screen, the number 2 itself ?
two dots ? . .
2 ?
II ?
兩 or 两 ??
ɳ ??

I hope you see that nobody can see a photon, photon is a name by convention and not a real thing

a reply to: KrzYma

hey I wanna learn how to post using Chinese characters!!

hey I gotta new question.

i Weigh 250lbs. i have an average gait of 20 inches and I walk on average 1.5 Mile's a day.

daily how much work am I performing?

i need to know the answer soon EDD wants to know how much work I've done in the last three months or they won't send me any unemployment money.

originally posted by: BASSPLYR
a reply to: KrzYma

hey I wanna learn how to post using Chinese characters!!

copy / paste

originally posted by: combatmaster
a reply to: Arbitrageur

theoretically speaking, if you could somehow transport a high powered telescope and human being to a point in the universe that light from earth has not yet reached.... technically you would be able to see the history of earth (e.g. the light that has left earth 2000 years ago would be seen by the telescope hence you would see 2000 years in the past).

similar to the way we see distant stars....

now, i know this presents many technical difficulties probably damn near impossible to achieve, but im not talking about the feasibility of this, theoretically i want to know if im wrong, if my perception of the way light works over vast distances is somewhat on track with reality!

Thanks for taking the time to answer this, its been on my mind for some time!

As you probably know, the Hubble space telescope is only about one light second away from the moon, and it can't even see enough detail of the moon to see the Apollo landing sites.

The other problem you'd have as the telescope moves further and further from Earth, is that the light from the sun would tend to obscure the Earth, which is why it would be much easier to see the light from the sun 2000 years ago than light from the Earth. The way we detect a lot of exoplanets isn't by seeing them directly, it's by seeing how much dimmer the star looks when the planet passes in front of the star, or by noting the gravitational wobble of the star as the planet tugs on it from side to side, which, with the sun being 333000 times more massive than Earth isn't much of a wobble.

So if you re-phrase the question to "can you put a telescope 2000 light years from our sun, and see what our sun looked like 2000 years ago", the answer is "yes". It would be very difficult to observe the Earth from that distance, as we know from the difficulty we have in observing exopanets directly.


a reply to: KrzYma
I don't understand your semantics about 2.

Light is quantized and if you had read the link about the frog's eye it talks about how they can count the packets. You can call it a "KrzYma" instead of a photon if you want, but it's still a bundle of light with a certain amount of energy, and you can't make it any smaller (less energetic) at the same frequency.

a reply to: Arbitrageur

what I was saying about supermassive black holes. On a big scale we can see galaxy cluster super groups formation and count how many of them showed up on the screen so far. Also, there may be number of undetected black holes wondering across cosmos.

originally posted by: Arbitrageur

originally posted by: bhaal
My question is this why is our known universe mostly matter, what happened to all the anti-matter.

This question is based on the assumption that at the start of the universe matter/anti-matter ratio was 50/50.

We don't know the answer, it's an unsolved problem.

One idea is there could be some kind of slight asymmetry between matter and anti-matter but we haven't found it yet and we're still trying to figure out what it is. There are other ideas too.

may be predominating 'spin' of the universe had anti matter to mostly canceled out? May be all of it)



cheers

a reply to: Arbitrageur

So if you re-phrase the question to "can you put a telescope 2000 light years from our sun, and see what our sun looked like 2000 years ago", the answer is "yes". It would be very difficult to observe the Earth from that distance, as we know from the difficulty we have in observing exopanets directly.

So theoretically speaking ofcourse, you would be able to see into the past... now isnt that something! If you think about it, the universe is therefore a mirror of time rather than a sea of space! or maybe its the same thing....

sorry for the rant and thanks for the answer and more accurately worded revision of my question

originally posted by: combatmaster
So theoretically speaking ofcourse, you would be able to see into the past... now isnt that something! If you think about it, the universe is therefore a mirror of time rather than a sea of space!

Speaking of mirrors my crazy idea was that we could see Earth's past if there was a mirror in space we could aim a telescope at that was positioned perfectly so Earth's past light was reflected back from where the earth was to where it is now, not an easy feat considering all the motions of the earth over time, rotating, orbiting the sun which is orbiting the galaxy.

The problem is you'd need a telescope bigger than Earth to see much detail if the mirror was far away to look far into the past, so even though it's totally impractical, it's still a cool idea. And what IS practical is that we look into the past every time we see an image from the Hubble telescope, like the nebula in my avatar. Astronomers think that nebula doesn't even exist today, so that's an image from 7000 years in the past. It may not be Earth's past, but it's still the past and that's pretty cool.

sorry for the rant and thanks for the answer and more accurately worded revision of my question

You're welcome and thanks for the interesting question, which is something I like to think about myself.

originally posted by: darkorange
a reply to: Arbitrageur

Also, there may be number of undetected black holes wondering across cosmos.

That's what the gravitational microlensing observations were attempting to find. We might have a hard time seeing black holes, but we think we should be able to detect their gravitational influence from the way they magnify light from more distant objects. There don't appear to be enough of them or other massive objects we call MACHOs, to explain all the mass we think must be out there.

originally posted by: KrzYma
a reply to: Arbitrageur
so.. rod cell from a frog's eye react to EM radiation at a wavelength of 532 nano-meters.
where is the photon ???

OK, another example, how does the number 2 looks like ??
not the shape we draw on paper or on the screen, the number 2 itself ?
two dots ? . .
2 ?
II ?
兩 or 两 ??
ɳ ??

I hope you see that nobody can see a photon, photon is a name by convention and not a real thing

Do you think your a Buddhist monk? We can call something anything we like it doesn't change its properties or have any bearing on its existence. Your argument is silly. If I chose to call a photon a purple dinosaur it's still a photon. As for wavelengths I think you are majorly confused no where did we discuss the wavelengths a frog can see. Yes a frog can see green light but hardly what was being discussed or even relevant for that matter.

Though inadvertently you prove they do exist. The shorter the wavelength the higher the energy and yet the speed of light remains the same for all wavelengths. The constant value of the speed of light in vacuum goes against our intuition: we would expect that high energy (short wavelength) radiation would move faster than low energy (long wavelength) radiation. We can consider light as a stream of minute packets of energy, photons, which create a pulsating electromagnetic disturbance.

The energy of the photon is not changed, but the wavelength is.This immediately tells us out wavelengths are quantized. What do we call the quantized light photons. Please in the future at least try to understand the topic from something other then an electrical engineer. Physics goes much deeper then just the frequency or wavelength.