Many students learn about the Doppler effect in physics class, typically as part of a discussion of why the pitch of a siren is higher as an ambulance approaches and then lower as the ambulance passes by. The effect is useful ...
General Physics
Aug 3, 2010
21
1
During a thunderstorm, we all know that it is common to hear thunder after we see the lightning. That's because sound travels much slower (768 miles per hour) than light (670,000,000 miles per hour).
Optics & Photonics
Nov 26, 2014
14
3
Astronomers have spotted three giant black holes within a titanic collision of three galaxies. Several observatories, including the Chandra X-ray Observatory and other NASA space telescopes, captured the unusual system.
Astronomy
Sep 25, 2019
24
2088
Our unfolding understanding of the universe is marked by epic searches and we are now on the brink of discovering something that has escaped detection for many years.
General Physics
Feb 24, 2014
59
0
It's one of the big cosmology debates: The universe is expanding, but how fast exactly? Two available measurements yield different results. Leiden physicist David Harvey adapted an independent third measurement method using ...
Astronomy
Nov 17, 2020
27
6647
Light travels at a speed of about 300,000,000 meters per second as light particles, photons, or equivalently as electromagnetic field waves. Experiments led by Hrvoje Petek, an R.K. Mellon professor in the Department of Physics ...
Optics & Photonics
Dec 23, 2020
0
8972
Some physical principles have been considered immutable since the time of Isaac Newton: Light always travels in straight lines. No physical object can change its speed unless some outside force acts on it.
General Physics
Jan 21, 2015
12
3765
The detection of four short bursts of radio waves, possibly arising from explosions billions of light years away, could be powerful tools to study our Universe, according to research published in Science.
Astronomy
Sep 27, 2013
12
2
Technion researchers have demonstrated, for the first time, that laser emissions can be created through the interaction of light and water waves. This "water-wave laser" could someday be used in tiny sensors that combine ...
Optics & Photonics
Nov 29, 2016
1
2087
The colloidal diamond has been a dream of researchers since the 1990s. These structures—stable, self-assembled formations of miniscule materials—have the potential to make light waves as useful as electrons in computing, ...
General Physics
Sep 23, 2020
4
1570
