In a remote galaxy, two neutron stars circled one another in a ballet of ultimate destruction and inevitable creation. Both objects were the remnants of massive stars, probably from a binary system, that had become supernovae long before. Each was incredibly massive, with neutrons so closely packed that their cores became diamond. The dance, alas, could not go on forever and the stars collided, releasing unimaginable energy and sending gravitational waves speeding through the fabric of space-time.
In 2017, 1.3 billion years later, astronomers detected those waves with the Laser Interferometer Gravitational-wave Observatory. Albert Einstein’s prediction that the universe should be filled with such faint ripples caused by gravity from massive objects included sources such as neutron star mergers. Yet finding a disturbance in the fabric of space-time from this kind of event had proven elusive until then. When news of the detection of gravitational waves broke, the media wanted to know what else happens when neutron stars collide. Astronomers explained that, beyond the destruction of the stars and the ripples in space, such events also create all the heavy elements we know in the blink of an eye. But what did the media key into? That gold comes from outer space.
In arguing against nuclear war, Dr. Tsipis said he came « to believe that reason must prevail. »
A curious boy who gazed at the stars from his mountainside Greek village and wondered how the universe came to be, Kosta Tsipis was only 11 when news arrived that the first atomic weapon had been dropped on Hiroshima, Japan.
“After the bomb went off, I sent away for a book because I wanted to understand it,” he told the Globe in 1987.
Prof. Dr. Thomas Kenkmann, geologist from the University of Freiburg’s Institute of Earth and Environmental Sciences, together with mineralogist Prof. Dr. Wolf Uwe Reimold from the University of Brasilia, Brazil, and Dr. Manfred Gottwald from the German Aerospace Center (DLR) published an atlas providing a comprehensive overview of all known impact craters on every continent. The authors present the more than 200 terrestrial impact sites in high-resolution topographic maps and satellite images, complete with detailed geological descriptions and photographs of the crater structures and their rocks. They also explain the essential details of each impact event.
The formation of craters by asteroid and comet impact has always been a fundamental process in the solar system, explains Kenkmann. As the planets developed along with their moons, these impacts played an important part in accreting planetary mass, shaping the surfaces of planetary bodies, and later also influencing their development. And larger meteorite impacts eventually affected the development of life on Earth.
Today, mapping of what can still be seen of the impact structures on the Earth’s surface can be done by satellites in low Earth orbit. From 2010 to 2016, the DLR successfully measured the Earth’s surface with the radar satellites of the TanDEM-X mission. The acquired data allowed, for the first time, to derive a worldwide terrain model with a height accuracy of up to one meter. From this global digital elevation model the authors have been able to produce this complete topographic atlas of 600 pages with information about all terrestrial impact craters known to date.
Astronomers at the University of Hawaii issued a statement on October 26, 2020, revealing critical new findings linked to the large near-Earth asteroid 99942 Apophis, which is expected to pass close to Earth in 2029, 2036 and again in 2068. Dave Tholen and collaborators announced they have now detected a Yarkovsky acceleration on asteroid Apophis, arising from a minuscule push imparted by sunlight. This force is particularly important for asteroid Apophis, the scientists in Hawaii said, because it relates to the possibility of an Earth impact in 2068.
Tholen and colleagues used the 323-inch (8.2-meter) Subaru Telescope at Mauna Kea, Hawaii, to make the new observations. Their work suggests that the huge space rock – whose estimated diameter is between 1,115 and 1,214 feet (340 to 370 meters) – is drifting more than 500 feet (about 170 meters) per year from its expected position in its orbit.
Certain cyber-artificial intelligence attacks could pose an existential threat to the US and the West, former US cyber command chief, Maj.-Gen. (ret.) Brett Williams said on Tuesday.
Speaking as part of Cybertech’s virtual conference, Williams said, “artificial intelligence is the real thing. It is already in use by attackers. When they learn how to do deepfakes, I would argue this is potentially an existential threat.”
Sixty Six million years ago a 14-kilometer long, Mount-Everest sized asteroid blasted a hole in the ground, when at the moment of impact, “the top of it might have still towered more than a mile above the cruising altitude of a 747,” writes Peter Brannen in Ends of the World. “In its nearly instantaneous descent, it compressed the air below it so violently that it briefly became several times hotter than the surface of the sun, hitting Earth with enough force enough to lift a mountain back into space at escape velocity, releasing the equivalent of 100 million megatons of TNT creating a 20-mile deep, 110-mile hole and sterilizing the remaining 170 million square miles of the ancient continent of Pangaea, killing virtually every species on Earth and, oddly, paving the way for the emergence of the human species.”
In a recent study of the upper atmosphere of Venus, finding the chemical fingerprint of phosphine has led to speculation that it may be tied to airborne life high in the clouds of our sister planet [1]. We harbour similar suspicion of microbial life on Mars [2], Saturn’s moon Enceledus [3], and Europa, the icy Galilean of the Jovian system [4]. The dwarf planet Ceres of the asteroid belt could be added to that list also, with recent evidence of oceanic water [5], while more exotic variations of life may exist on Titan, which is known to be teeming with organic materials [6]. Should we be more wary of our Solar System as an environment to explore, and the potential of pathogens we may encounter?
If one rewinds 500 years, to when exploration of new worlds involved sailing the oceans, the discovery of the Americas introduced viruses which decimated the native population at that time [7]. That in itself was far from a unique event in history, of course. There have been many occurrences throughout history where travel between distant lands has resulted in the introduction of devastating plagues to one population or the other — not least the Black Death, which arrived in Europe from commercial travel with Asia in the 1300s [8]. Meanwhile, 2020 has reminded us how a novel virus can prove virtually unstoppable from spreading worldwide in a matter of months and reaching pandemic level, once introduced to our now interconnected world [9].
Indeed when the first astronauts returned from the Moon in the 60s, they had to undergo weeks of quarantine as a precaution against introducing a lunar pathogen to Earth [10]. We now know the Moon to be a sterile world, but this should not give us a false sense of security when visiting and returning from other worlds, which are far more likely to harbour microbial life. It is quite plausible to consider that any microbes which have evolved to survive in the harsh environments on other worlds could multiply out of control if introduced to a more fertile environment on Earth. The likelihood of any such foreign microbes being capable of becoming infectious pathogens to our species is difficult to measure, but one could still cause problems regardless, by undermining Earth’s ecosystem in competing with native microbial life as a runaway invasive species.
Fortunately, due to the vast distances involved in inter-planetary travel, returning astronauts would likely show symptoms of infection from any dangerous pathogen long before reaching home, as such a journey would be expected to take many months, even with more advanced propulsion technology than we use in space travel today. That is not to say they could not inadvertently return with microbial life on board — or even on the exterior of craft: Earth’s tardigrades, for example, have proven quite durable in journeys into outer space [11].
