Carl Sagan in the context of "Popular science"

The Voyager Golden Record contains 116 images and a variety of sounds. The items for the record, which is carried on both the Voyager 1 and Voyager 2 spacecraft, were selected for NASA by a committee chaired by Carl Sagan of Cornell University. Included are natural sounds (including some made by animals), musical selections from different cultures and eras, spoken greetings in 55 languages, human sounds like footsteps and laughter, and printed messages from President Jimmy Carter and U.N. Secretary-General Kurt Waldheim.

Somnium (Latin for "The Dream") — full title: Somnium, seu opus posthumum De astronomia lunari — is a novel written in Latin in 1608 by Johannes Kepler. It was first published in 1634 by Kepler's son, Ludwig Kepler, several years after the death of his father. In the narrative, an Icelandic boy and his witch mother learn of an island named Levania (the Moon) from a daemon ("Levana" is the Hebrew word for the moon). Somnium presents a detailed imaginative description of how the Earth might look when viewed from the Moon, and is considered the first serious scientific treatise on lunar astronomy. Carl Sagan and Isaac Asimov have referred to it as one of the earliest works of science fiction.

Terraforming or terraformation ("Earth-shaping") is the hypothetical process of deliberately modifying the atmosphere, temperature, surface topography or ecology of a planet, moon, or other body to be similar to the environment of Earth, with the goal of making it habitable for humans.

The concept of terraforming developed from both science fiction and actual science. Carl Sagan, an astronomer, proposed the planetary engineering of Venus in 1961, which is considered one of the first accounts of the concept. The term was coined by Jack Williamson in a science-fiction short story ("Collision Orbit") published in 1942 in Astounding Science Fiction.

Pale Blue Dot is a photograph of Earth taken on February 14, 1990, by the Voyager 1 space probe from an unprecedented distance of over 6 billion kilometers (3.7 billion miles, 40.5 AU), as part of that day's Family Portrait series of images of the Solar System.

In the photograph, Earth's apparent size is less than a pixel; the planet appears as a tiny dot against the vastness of space, among bands of sunlight reflected by the camera. Commissioned by NASA and resulting from the advocacy of astronomer and author Carl Sagan, the photograph was interpreted in Sagan's 1994 book, Pale Blue Dot, as representing humanity's minuscule and ephemeral place amidst the cosmos.

The faint young Sun paradox or faint young Sun problem describes the apparent contradiction between observations of liquid water early in Earth's history and the astrophysical expectation that the Sun's output would have been only 70 percent as intense during that epoch as it is during the modern epoch. The paradox is this: with the young Sun's output at only 70 percent of its current output, early Earth would be expected to be completely frozen, but early Earth seems to have had liquid water and supported life.

The issue was raised by astronomers Carl Sagan and George Mullen in 1972.Proposed resolutions of this paradox have taken into account greenhouse effects, changes to planetary albedo, astrophysical influences, or combinations of these suggestions. The predominant theory is that the greenhouse gas carbon dioxide contributed most to the warming of the Earth.

Kip Stephen Thorne (born June 1, 1940) is an American theoretical physicist and writer known for his contributions in gravitational physics and astrophysics. Along with Rainer Weiss and Barry C. Barish, he was awarded the 2017 Nobel Prize in Physics for his contributions to the LIGO detector and the observation of gravitational waves.

A longtime friend and colleague of Stephen Hawking and Carl Sagan, he was the Richard P. Feynman Professor of Theoretical Physics at the California Institute of Technology (Caltech) from 1991 until 2009. He has spoken about the astrophysical implications of the general theory of relativity. He was a scientific consultant for the Christopher Nolan films Interstellar and Tenet.