A Virgin( not Virgo )

[iceworks]

Hi, this is my first time on the ice in space forum- so hello to everyone. I have only just begun my obsession with the sky, but I think it could be a long and interesting one. Physics was never my strongest subject at uni. but I was wondering about the speed of light. It travels at about 300,000 kms/sec, does this mean that its speed is constant or does a photon accelerate as it is emitted from its source and then reach a maximum speed of 300,000 kms/sec , or is this an average? If light can be bent, distorted or just sucked into nothingness by gravity/black holes, does this change the speed of light and hence the accuracy of distance calculations?

[matt]

I'm not much of a specialist in this field, but welcome anyway.

That's an awfully familiar user name. Hmmmmm

[iceworks]

I assume iceman( Sir Post a Lot ) is well known. I on the other hand am not, however I do own and operate an Iceworks, hence the name.

[Ric]

Welcome to the group, that's a very good question, I've never actually thought about it myself but I will be interested as well to see the answer.

Cheers

[Omaroo (Chris Malikoff)]

Originally Posted by iceman2

I assume iceman( Sir Post a Lot ) is well known. I on the other hand am not, however I do own and operate an Iceworks, hence the name.

hehe... yup... he owns this website. No matter.. I like the name so much I might re-register as "Iceman III" just to clear things up around here.

[iceman (Mike)]

iceman2, can you please think of a new name. I meant to PM you when you registered but forgot. Even IceWorks is better than iceman2

I'll PM you later for your decision

btw

[ving (David)]

welcome to here!
as for your question... well i cant even bring myself to read it at the moment but will give it a go after i get rid of this darn head cold...
oh yes, have pitty on me please!

[ballaratdragons (Ken)]

Hi Ice 2.

The speed of light is 300,000 in a Vacuum. Meaning that it is possible to be altered in a non-vacuum.

I did read an article on the net about changing the speed of light, but I can't find it now. I will go look for it again, and if I can find it I will stick the link in here.

[Meade bloke]

Imitation is the highest form of flattery. lol.

does a photon accelerate as it is emitted from its source and then reach a maximum speed of 300,000 kms/sec

Would have to accelerate from a point source , my thinking

[Argonavis (William)]

Originally Posted by iceman2

but I was wondering about the speed of light. It travels at about 300,000 kms/sec, does this mean that its speed is constant or does a photon accelerate as it is emitted from its source and then reach a maximum speed of 300,000 kms/sec , or is this an average? :

When an electron drops into a lower orbit around the nucleus of an atom, it emits a photon of electromagnetic radiation. All electromagnetic radiation (from radio waves to high energy X-rays) travels at about 300,000 kms per second in a vacuum. Einstein said this speed is fixed, so it will not vary from the time of emission to when it is eventually absorbed by another atom. It will not accelerate, rather is emitted at the "speed of light".

Originally Posted by iceman2

If light can be bent, distorted or just sucked into nothingness by gravity/black holes, does this change the speed of light and hence the accuracy of distance calculations?

According to Einstein, as the speed of light is fixed, it does not change under any circumstances. It's path can be deflected by gravity, but it is not slowed.

However our perspective can result in us seeing superluminal velocities, where light appears to be moving faster than the speed of light, and zero velocities, such as at the event horizon at a black hole, where time appears to freeze, and we would observe a photon of light that does not appear to be moving at all. The latter is due to time slowing down.

This is really interesting stuff, and I suggest you try your local public library for anything on Einstein, cosmology, relativity and black holes. A "brief History of Time" is recommended.

[Argonavis (William)]

Originally Posted by iceman2

does this change the speed of light and hence the accuracy of distance calculations?

No

[Ric]

Hi Argonavis, that was a very good answer and it has definately got me interested to read more about it. I was in a local bookstore on the weekend and saw "A brief History of Time" on sale for half price, I think I'll go back and see if it is still there.

Cheers

Ps: Get well soon Ving

[Dujon]

I too recommend Hawking's A Brief History of Time. You might also find that Brian Greene's The Elegant Universe helpful as well. Hawking covers most aspects but Greene (although the book is essentially about string theory) has a well written introduction - about a quarter of the book - which, to me anyway, helped clarify some of Hawking's descriptions.

[ving (David)]

Originally Posted by Ric

Hi Argonavis, that was a very good answer and it has definately got me interested to read more about it. I was in a local bookstore on the weekend and saw "A brief History of Time" on sale for half price, I think I'll go back and see if it is still there.

Cheers

Ps: Get well soon Ving

will do, back at work today but still not feeling that good... time is what i need.

[DobDobDob (Ron)]

Okay after a little research, Einstein's special theory of relativity can be broken down to the following few sentences:

The whole theory is based on two postulates:-

1. The laws of physics take the same form in all inertial frames.
2. In any inertial frame, the velocity of light c is the same whether the light is emitted by a body at rest or by a body in uniform motion.

You can read more here: http://www-groups.dcs.st-and.ac.uk/~history/HistTopics/Special_relativity.html

[VK2KR]

Hi

May I suggest looking at this URL regarding "light speed"

http://science.nasa.gov/headlines/y2..._stoplight.htm


Alex
aka VK2KR

[DobDobDob (Ron)]

Top Posting Alex that is a great article and very up-to-date. It doesn't answer the original question of acceleration, which is answered by the Special Theory of Relativity, however the stopping of light and restarting of it to continue it's journey is intoxicatingly interesting and absorbing. Thank you for posting the URL.

As an afterthought, I believe TOE is close at hand

[seeker372011 (Narayan)]

personally I find Stephen Hawking quite boring to read...his first book outsold most books other than the bible but was possible the most unread book of all time. (i must be a sucker for punishment I also own a Universe in a Nutshell as well as a briefer history of Time or whatever its called I cant recall at this late hour in the day)
I'd recommend The Dancing Wu Li Masters by Gary Zukov as a much more readable book even though its quite old

[iceworks]

Only too happy to change my name in deference to you. How do I do this? Just set up a new user name or is there a way to change the one I already have?

[iceman (Mike)]

Done