“Planet Earth Report” provides descriptive links to headline news by leading science journalists about the extraordinary discoveries, technology, people, and events changing our knowledge of Planet Earth and the future of the human species.
“We were all getting together and asking: what does this thing mean?” says radio astronomer Michael Johnson at Harvard’s Black Hole Initiative about the glowing bright orange ring around the now iconic black hole the size of our solar system at the center of the monster elliptical galaxy M87 –the largest, most massive galaxy in the nearby universe–described by astronomers on April 10, 2019 as “paradoxical, intriguing, frightening” and “the end of spacetime.”
In the fall of 1967, Princeton’s great quantum physicist, John Archibald Wheeler was giving a lecture on pulsars at a conference where he was arguing that we should consider the possibility that the center of a pulsar is a gravitationally completely collapsed object. He remarked that one couldn’t keep saying “gravitationally completely collapsed object” over and over. That we needed a shorter descriptive phrase. “How about black hole?” asked someone in the audience, giving birth to the name of one of the most paradoxical objects in the universe.
“In the end, the most improbable and hence the most puzzling aspect of space is its very existence. The simple fact that we live in an apparently smooth and regular three dimensional world represents one of the greatest challenges to the developing quantum theory of gravity,” wrote physicist Lee Smolin in Three Roads To Quantum Gravity. “If you look around at the world seeking mystery, you may reflect that one of the biggest mysteries is that we live in a world in which it is possible to look around, and see as far as we like. The great triumph of the quantum theory of gravity may be that it will explain to us why this is so.”
On Tuesday we wrote that Mars tugs at the human imagination like no other planet. “It’s there,” said astronaut Buzz Aldrin, “waiting to be reached.” Today, NASA launched the Perseverance rover that will, if all goes as planned, touch down at the Jezero Crater landing site in February 2021 as a robotic explorer. Jezero, a 45-kilometre-wide crater is home to the remains of an ancient river delta. NASA researchers have detected deposits of hydrated silica from previous flybys –a mineral that’s especially good at preserving microfossils and other signs of past life.
“In less than a hundred years, we have found a new way to think of ourselves,” observed Stephen Hawking. “From sitting at the center of the universe, we now find ourselves orbiting an average-sized sun, which is just one of millions of stars in our own Milky Way galaxy.” Some of the oldest stars in the universe are found in ancient globular clusters that orbit around the plane, the nucleus, of our home galaxy, which is circled by 150 globular clusters, harboring hundreds of thousands, and sometimes millions of stars, formed very early in the vast halo surrounding the embryonic Milky Way before it flattened to form the spiral disc.
“The oldest traces of life are fossils of marine microbes dating back almost 3.5 billion years. It was in the oceans that multicellular organisms evolved; their oldest fossils date back to about 2 billion years ago,” observes Carl Zimmer in 翻墙一点通. “Microbes may be invisible to the naked eye,” he adds,”but collectively they dwarf all the ocean’s whales, its coral reefs, and all other forms of marine life.”
It’s been said that Mars tugs at the human imagination like no other planet. “It’s there,” said astronaut Buzz Aldrin, “waiting to be reached” and this July, 2020, NASA is planning to launch a mission to grab its first ‘taste’ of the Red Planet –the only known planet inhabited solely by robots. On Thursday, 30 July, NASA will launch the Perseverance rover that will, hopefully, touch down at the Jezero Crater landing site in February 2021 as a robotic explorer.
