Discovered Lights Mass?

[Nim]

From: RedColony.com: Propulsion on a Manned Martian Expedition (http://www.redcolony.com/articles/030115.html)

"Photon Reaction: Until recently, scientists believed that photons (light) had no mass, but recently, it was discovered that they did have mass. Light has mass. Light is reflected by reflective surfaces. For every action, there is an equal and opposite reaction. That means that..."

Anyone know what "Kevin Reimund" is talking about?

[MathematicalPhysicist]

i havent read the link youve given but from the quote you gave i think he still believes in the thoery of newton that light is actually a snooker-like particles, and therefore have mass but according to quantum mechanics which replaced newton's theory about particles this isnt the case.

[pmb_phy]

Originally posted by Nim
From: RedColony.com: Propulsion on a Manned Martian Expedition (http://www.redcolony.com/articles/030115.html)

"Photon Reaction: Until recently, scientists believed that photons (light) had no mass, but recently, it was discovered that they did have mass. Light has mass. Light is reflected by reflective surfaces. For every action, there is an equal and opposite reaction. That means that..."

Anyone know what "Kevin Reimund" is talking about?

The author is confusing relativistic mass with proper mass. He's speaking of radiation pressure and that was established by Poincare And Poisson over 100 years ago. The idea that electromagnetic radiation (i.e. light) had mass was first speculated by Poincare in 1900 as I recall. The issue was then raised again by Einstein in 1906 with his famous "photon in a box" experiment."

See http://www.geocities.com/physics_world/sr/einsteins_box.htm