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October 27, 2021 Archives

Wednesday, October 27, 2021

TRACKING WITH CLOSEUPS: Starship Mars Missions Before Refuelling on Mars

SpaceX's plans for an Earth-Mars transportation infrastructure assume the ability to refuel Starships on Mars with methane and oxygen propellant manufactured from resources on Mars (carbon dioxide and water, plus electricity generated from solar or nuclear power), a process called “in-situ resource utilisation” (ISRU). But first the propellant plant has to be delivered to Mars, so initial Starship missions will necessarily be one-way, at least until the plant they deliver has produced sufficient fuel to permit them to return. Marcus House looks at the logistics of this, including the mass budget for a solar powered propellant plant.

Posted at 13:22 Permalink

CONTEXT: How Virtual Worlds Work—Part 5, Ownership of Virtual Objects

Posted at 12:55 Permalink

CONTINUITY: Avi Loeb: “Was Our Universe Created in a Laboratory?”

In his 1999 book, The Life of the Cosmos, Lee Smolin suggested that the reason the universe appeared to be so fine-tuned for complexity and life was what he termed “cosmic natural selection”, in which new baby universes were born during the formation of black holes, each with physical properties that differed from their parent universe due to quantum uncertainty. Universes in which, for example, star formation was impossible would have no progeny and die out, and those that collapse to a single black hole would create only one child universe. Only those in which the initial conditions allowed the formation of massive stars would produce a multitude of black holes, and these would come to dominate the population of universes. But the massive stars that end up as black holes are the prerequisite for creating the heavy elements which are necessary to form planets and living beings. So, we shouldn't be surprised to find ourselves in a universe which appears to have been fine tuned to create the requirements for our form of life.

Now, Harvard astronomy professor Avi Loeb proposes an even more breathtaking speculation in a Scientific American opinion piece, “Was Our Universe Created in a Laboratory?”. Loeb argues that an advanced technological civilisation, which he calls “Class A”, will eventually develop the capability, perhaps by manipulating dark matter and dark energy, or via some means we haven't yet imagined, to perform the ultimate experiment—creating baby universes. If they can control the physical parameters of these universes, they would naturally fine tune them so they would, in turn, eventually produce their own Class A inhabitants. The process of natural selection would, then, operate on the scale of the multiverse, with universes that never produce a Class A civilisation producing no progeny, while those that eventually evolve Class A civilisations are fruitful and proliferate.

Loeb considers humanity at present a Class C civilisation, as we are unable to re-create a habitat for ourselves when the Sun dies. “A class B civilization could adjust the conditions in its immediate environment to be independent of its host star. A civilization ranked class A could recreate the cosmic conditions that gave rise to its existence, namely produce a baby universe in a laboratory.”

Posted at 11:28 Permalink

CONTEXT: Albert Einstein and his Flying Car

This sequence was filmed on the Warner Brothers special effects stage at Warner Brothers in Los Angeles during a Einstein's visit to California in 1931. It has been colourised and re-processed to 4K, 60 frames per second video.

Einstein was not only a film star, but also an inventor. Just a few months earlier, he and Leo Szilard were granted U.S. patent 1,781,541 for the Einstein-Szilard Refrigerator.

Posted at 10:43 Permalink