“The final stage in the life of a star,” observes physicist Carlo Rovelli in Seven Brief Lessons on Physics, “where the quantum fluctuations of space-time balance the weight of matter, is what is known as a ‘Planck star’. If the sun were to stop burning and to form a black hole, the event horizon would measure about six kilometers in diameter. The black hole’s event horizon is not a physical barrier, but simply the boundary where the black hole’s gravitational field becomes so intense that the escape velocity exceeds the speed of light. Nothing, not even light, can escape the event horizon.
Another amazing week in our Universe beyond –from a new type of habitable planet to China’s plan for a spacecraft 30 times the size of the ISS to the new reality of UFOs and the detection of gravitational waves that could be from dark matter particles.
“Eliminating the singularity or Big Bang– which has its origins in the late 1920s when US astronomer Edwin Hubble discovered that almost all galaxies are moving away from each other at ever-faster velocities– brings back the bouncing Universe on to the theoretical stage of cosmology. The absence of a singularity at the start of spacetime opens up the possibility that vestiges of a previous contraction phase may have withstood the phase change (between contraction to expansion) and may still be with us in the ongoing expansion of the Universe,” said Brazilian physicist Juliano Cesar Silva Neves.
“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.
“It is possible that there’s a zoo of different compact objects, and while some of them are the black holes that follow Einstein and Hawking’s laws, others may be slightly different beasts,” says Maximiliano Isi, a NASA Einstein Postdoctoral Fellow in MIT’s Kavli Institute for Astrophysics and Space Research and lead author of a study about a signal from a gravitational wave merger.
This week’s newsletter covers news reports from “Why aren’t we talking more about UFOs?” asks Megan McArdle in the Washington Post to the first matter in the universe may have been a perfect liquid to the Milky Way’s supermassive black hole, Sagittarius A*, may actually be a colossal glob of dark matter.