Mark Fischetti

1 week ago | scientificamerican.com | Mark Fischetti

1975Introducing the Videodisc“A ‘videodisc’ system that presents recorded pictures and sound on a television set will be put on the market next year by North American Philips Corporation and MCA Inc. The player looks somewhat like a phonograph, and the record resembles a phonograph record. The distinctive feature is an optical ‘stylus,’ which replaces the needle of the phonograph. The stylus is a scanner employing a one-milliwatt helium-neon laser as its sensor.

1 month ago | scientificamerican.com | Mark Fischetti

1975Mysterious Gamma Rays from Space“As a result of the Partial Test-Ban Treaty of 1963, which prohibited nuclear explosions in space, the U.S. launched five satellites to act as monitors. Each satellite was equipped with a detector designed to respond to gamma rays from a nuclear explosion. Detectors aboard two or more satellites could determine the position of the source.

2 months ago | scientificamerican.com | Mark Fischetti

1975Chemical Warfare Ill Defined“Biological weapons have been negotiated out of the arsenals of most of the world’s major military powers, and poison gas may be on the way out. In January the U.S. acceded to the Geneva Protocol of 1925, banning any first use of gas and bacteriological weapons, and to the Biological Weapons Convention of 1972.

Jan 21, 2025 | scientificamerican.com | Mark Fischetti

1975Radical Revision of Continents and Poles“Of the various hypotheses that preceded the modern theory of plate tectonics, one version propounded by Alfred Wegener early in the 20th century stands out. Wegener had access to only a small part of the information available today, yet his theory anticipated much that is now fundamental, including the movement of the continents and the wandering of the poles.

Nov 19, 2024 | scientificamerican.com | Mark Fischetti

1974More Alcohol Found in Space“Is there intelligent life elsewhere in the universe? Positive evidence facetiously adduced was that whereas methyl alcohol had been discovered in interstellar space, ethyl alcohol (the potable kind) had not. Clearly someone had consumed the stuff. But in October a group of [researchers] used a highly sensitive spectrometer to investigate the dense cloud of gas and dust designated Sagittarius B2, a rich source of most of the known molecules in space.