The Naked Scientists

The Naked Scientists Forum

Author Topic: Can powerfull gamma rays push objects?  (Read 3103 times)

Offline taregg

  • Sr. Member
  • ****
  • Posts: 168
    • View Profile
Can powerfull gamma rays push objects?
« on: 07/05/2013 17:47:42 »
 same like walls and buildings until falls down....
« Last Edit: 03/08/2013 15:25:46 by taregg »


 

Offline yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11999
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
Re: does gamma ray can push objects
« Reply #1 on: 08/05/2013 18:32:19 »
 

Offline Pmb

  • Neilep Level Member
  • ******
  • Posts: 1838
  • Physicist
    • View Profile
    • New England Science Constortium
Re: Can gamma rays push objects?
« Reply #2 on: 10/05/2013 00:01:58 »
same like walls and buildings until falls down....
I don't see why not. Most will pass right though matter. Some will scatter off electrons and other charged particles.
 

Offline Lmnre

  • Sr. Member
  • ****
  • Posts: 178
    • View Profile
Re: Can gamma rays push objects?
« Reply #3 on: 10/05/2013 16:16:51 »
Do you mean like the Sun's rays "pushing" on the vanes of a Crookes radiometer (aka "light mill") shown below?


source

How scientists found the reason behind the "pushing".
 

Offline lightarrow

  • Neilep Level Member
  • ******
  • Posts: 4586
  • Thanked: 7 times
    • View Profile
Re: Can gamma rays push objects?
« Reply #4 on: 12/05/2013 12:42:37 »
same like walls and buildings until falls down....
A light pulse's momentum is E/c where E is the pulse's energy. So, given enough energy, and independently on its frequency, a light pulse can push what you want. Just remember that, if you do it with a portable device, you receive the same momentum as recoil when you shoot the pulse  :D
 

Offline syhprum

  • Neilep Level Member
  • ******
  • Posts: 3822
  • Thanked: 19 times
    • View Profile
Re: Can gamma rays push objects?
« Reply #5 on: 12/05/2013 15:27:33 »
I understand a 300MW beam of visible light will produce a thrust of one N , will the same radiated power in gamma rays produce the same thrust as I would expect the greater momentum of the gamma ray photons to be modified by their reduced number. 
 

Offline lightarrow

  • Neilep Level Member
  • ******
  • Posts: 4586
  • Thanked: 7 times
    • View Profile
Re: Can gamma rays push objects?
« Reply #6 on: 12/05/2013 15:48:53 »
It's a question or a statement? However it's yes.
 

Offline syhprum

  • Neilep Level Member
  • ******
  • Posts: 3822
  • Thanked: 19 times
    • View Profile
Re: Can gamma rays push objects?
« Reply #7 on: 13/05/2013 19:04:25 »
So its the total energy of the beam that is relevant not the energy of individual photons, whenever this matter is mentioned the actual frequency of the radiation is always quoted but it could just as well be from the 198kHz Droitwich radio station as from a gamma ray source if the power was the same.
 

Offline lightarrow

  • Neilep Level Member
  • ******
  • Posts: 4586
  • Thanked: 7 times
    • View Profile
Re: Can gamma rays push objects?
« Reply #8 on: 13/05/2013 23:32:30 »
So its the total energy of the beam that is relevant not the energy of individual photons, whenever this matter is mentioned the actual frequency of the radiation is always quoted but it could just as well be from the 198kHz Droitwich radio station as from a gamma ray source if the power was the same.
Yes, of course assuming the same absorption power from the material at the two different frequencies, which is usually false (but it could be made equal, choosing suitable body and materials, having fixed the two frequencies).
« Last Edit: 13/05/2013 23:34:38 by lightarrow »
 

Offline taregg

  • Sr. Member
  • ****
  • Posts: 168
    • View Profile
Re: Can gamma rays push objects?
« Reply #9 on: 03/08/2013 15:23:52 »
 i think alpha decayrays can push objects not gamma rays is it correct ....
« Last Edit: 03/08/2013 23:01:27 by taregg »
 

Offline Pmb

  • Neilep Level Member
  • ******
  • Posts: 1838
  • Physicist
    • View Profile
    • New England Science Constortium
Re: Can powerfull gamma rays push objects?
« Reply #10 on: 04/08/2013 14:26:51 »
Do you mean like the Sun's rays "pushing" on the vanes of a Crookes radiometer (aka "light mill") shown below?


source

How scientists found the reason behind the "pushing".

The radiometer does not work by radiation pressure. It works by thermodynamics, i.e. the black side is heated more than the otherside. This heating causes a difference in pressure between the two sides and results in the arm turning. If it were radiation pressure which caused the turning then the arms would turn in a direction which is opposite than what is observed.

Look at the video above. Notice that it's turning the wrong way if it was light causing it to turn. Light is absorbed on the black side and reflected on the silver side. Therefore there is a greater force on the silver side. Yet the arms are turning the wrong way if this was the source of the torque.
« Last Edit: 04/08/2013 14:29:22 by Pmb »
 

Offline lightarrow

  • Neilep Level Member
  • ******
  • Posts: 4586
  • Thanked: 7 times
    • View Profile
Re: Can powerfull gamma rays push objects?
« Reply #11 on: 04/08/2013 16:07:58 »
i think alpha decayrays can push objects not gamma rays is it correct ....
No, it's false. Electromagnetic radiation (wich gamma rays belong, as well as x-rays, UV, light, infrared, microwaves, radio waves...) does have momentum (and so is able to push) as well as alpha particles. Read my first post again.

--
lightarrow.
« Last Edit: 04/08/2013 16:09:55 by lightarrow »
 

lean bean

  • Guest
Re: Can powerfull gamma rays push objects?
« Reply #12 on: 04/08/2013 16:42:55 »
ARRR, me hearties, hoist the solar sail and splice the mainbrace, and do something with the anchor.

http://en.wikipedia.org/wiki/Solar_sail

http://www.planetary.org/explore/projects/lightsail-solar-sailing/what-is-solar-sailing.html
« Last Edit: 04/08/2013 16:46:09 by lean bean »
 

Offline lightarrow

  • Neilep Level Member
  • ******
  • Posts: 4586
  • Thanked: 7 times
    • View Profile
Re: Can powerfull gamma rays push objects?
« Reply #13 on: 04/08/2013 16:47:12 »
ARRR, me hearties, hoist the solar sail and splice the mainbrace.

http://en.wikipedia.org/wiki/Solar_sail

http://www.planetary.org/explore/projects/lightsail-solar-sailing/what-is-solar-sailing.html
Yes. Unfortunately we still are not very used to that idea; the day we will be, people will stop asking if light can push objects or not  :)
 

lean bean

  • Guest
Re: Can powerfull gamma rays push objects?
« Reply #14 on: 04/08/2013 17:01:40 »
Nasa's Sunjammer is looking good for a November 2014 launch.
http://www.sunjammermission.com/
« Last Edit: 04/08/2013 17:03:37 by lean bean »
 

Offline evan_au

  • Neilep Level Member
  • ******
  • Posts: 4128
  • Thanked: 247 times
    • View Profile
Re: Can powerfull gamma rays push objects?
« Reply #15 on: 05/08/2013 09:44:46 »
In one sense, alpha particles would transfer momentum quite efficiently to matter, since they interact strongly with atomic nuclei.

X-Rays and Gamma Rays tend to go straight through many objects, and so are not so good at transferring momentum to the object.

Note that you should not intentionally expose yourself to excess nuclear radiation - its not good for you!
 

Offline Pmb

  • Neilep Level Member
  • ******
  • Posts: 1838
  • Physicist
    • View Profile
    • New England Science Constortium
Re: Can powerfull gamma rays push objects?
« Reply #16 on: 05/08/2013 14:37:59 »
ARRR, me hearties, hoist the solar sail and splice the mainbrace, and do something with the anchor.
rotfl!!
 

The Naked Scientists Forum

Re: Can powerfull gamma rays push objects?
« Reply #16 on: 05/08/2013 14:37:59 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums