Back in December 1990, during its flyby of Earth, NASA’s Galileo spacecraft, which studied the planet Jupiter and its moons, as well as several other Solar System bodies, pointed its instruments towards Earth, at the urging of Carl Sagan. And, it has found evidence of life on our planet. This can be a key to detect vegetation on exoplanets – which is a key to a possible intelligent extraterrestrial life.
In a paper published on Nature, researchers wrote “The Galileo spacecraft found evidence of abundant gaseous oxygen, a widely distributed surface pigment with a sharp absorption edge in the red part of the visible spectrum, and atmospheric methane in extreme thermodynamic disequilibrium. Together, these are strongly suggestive of life on Earth.”
Continue reading Earth can be a model for detecting vegetation on exoplanets
Earth, our beautiful blue planet. It is the third planet from the Sun, but above all, it is our home, the only astronomical object known to harbor life. Here are the best quotes about Earth.
Continue reading Earth Quotes – 10 Best Sayings about Earth
NASA’s asteroid-sampling OSIRIS-REx spacecraft captured a new Earth-Moon image on Jan. 17, 2018, from a distance of 39.5 million miles (63.6 million kilometers). Spacecraft used its NavCam1 imager to take this photo, as part of an engineering test. In the image, The Earth and the moon are just two bright dots against the vastness of black space – which reminds us of Carl Sagan’s famous speech: “That’s here. That’s home. That’s us.”
Continue reading OSIRIS-REx Captures New Earth-Moon Image from 39.5 Million Miles
It took 27 years, but finally, NASA’s New Horizons spacecraft beat Voyager 1’s record for being farthest from Earth while capturing images. Taken on December 5, 2017, New Horizons image of the open star cluster NGC 3532 (also commonly known as the Football Cluster or the Wishing Well Cluster) became the farthest image ever made by any spacecraft, breaking a 27-year record set by Voyager 1. But for a very short time! About 2 hours later, New Horizons broke its own record with images of two Kuiper Belt objects.
For a short time, the image below, New Horizons Long Range Reconnaissance Imager (LORRI) frame of the galactic open star cluster NGC 3532 (aka the Football Cluster or the Wishing Well Cluster), taken on December 5, 2017 (released on February 8, 2015), was the farthest image ever made by a spacecraft, breaking a 27-year record set by Voyager 1. New Horizons was 3.79 billion miles (6.12 billion kilometers or 40.9 astronomical units-AUNotes 1) from Earth when LORRI took the routine calibration image.
Continue reading New Horizons beats Voyager 1’s Record for being farthest from Earth while capturing images
Earth is actually a fragile and isolated rock, a “blue marble” in a vast, cold and hostile space. But only after seeing our planet from space we truly understood that. Seeing the Earth first time from a distance was a powerful experience which has changed the way we see our planet. Here are the top 10 most iconic photos of Earth from space.
Continue reading Top 10 Most Iconic Photos of Earth from Space
Carl Sagan’s famous quote says “The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of starstuff.” In that famous quote, Sagan makes reference to the whole universe started off with hydrogen and helium, all stars produce helium, and then stars over a certain mass threshold produce carbon, nitrogen, oxygen and lots of heavier elements – which are also the source of the life. The star stuff is inside us – every living thing on Earth.
But, even stars aren’t powerful enough to create heavy elements like silver, gold, and cesium. Since the 1950s, scientists have wondered: where do most of the elements in the periodic table come from?
Continue reading LIGO detects gravitational waves from neutron star merger
In 240 BC, the Greek astronomer, geographer, mathematician, music theorist and librarian Eratosthenes of Cyrene (c. 276 BC – c. 195/194 BC) calculated the circumference of the Earth without even leaving Egypt. Here’s how:
Eratosthenes knew that at local noon on the summer solstice (at the time of the longest day, about 21 June in the northern hemisphere) in Syene (modern Aswan, Egypt), the Sun was directly overhead – Syene was in fact slightly north of the tropic, though (1). Local noon is – technically when the sub-solar point is somewhere over your meridian, it’s noon for you. So, on that day, Syene is the sub-solar point of Earth (the sub-solar point on a planet is where its sun is perceived to be directly overhead). To learn more about the local noon and the subsolar point, see the article titled “How Earth Moves“.
Continue reading How Eratosthenes calculated the Earth’s circumference
The Earth is our one and only home. As Carl Sagan said (Pale Blue Dot: A Vision of the Human Future in Space), “On Earth, everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every “superstar,” every “supreme leader,” every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam.”.
But will we ever leave our home and visit other stars in the future?
Continue reading Will We Ever Visit Other Stars?
Our galaxy, “The Milky Way” is a barred spiral galaxy (a spiral galaxy with a central bar-shaped structure composed of stars) some 100,000-120,000 light-years in diameter, which contains 100-400 billion stars. It may contain at least as many planets as well. Our Sun (the Solar System) is located within the disk, about 27,000 light-years away from the Galactic Center, on the inner edge of one of the spiral-shaped concentrations of gas and dust called the Orion Arm.
The farthest spacecraft from Earth, NASA’s Voyager 1 Notes 1 probe took a photo of planet Earth in 1990, from a record distance of about 6 billion kilometers (3.7 billion miles, 40 AU) from Earth. The photo is known as the Pale Blue Dot. In the photograph, Earth is shown as a fraction of a pixel (0.12 pixel in size) against the vastness of space. It was a part of the solar system Family Portrait series of images.
Continue reading Pale Blue Dot
The Voyager 1 spacecraft, which had completed its primary mission and was leaving the Solar System, was commanded by NASA to turn its camera around and to take a photograph of Earth across a great expanse of space, at the request of Carl Sagan Notes 2.