WASP-76b, a planet where it rains iron; New technology uses artificial intelligence and RF communications to see through walls; A high speed robotic arm makes drone delivery more efficient for urban areas; An argument that faster than light travel is possible - in principle; and How to mine the moon for rocket fuel

Curating the Internet: Science and technology digest for

May 22, 2020

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Fresh and Informative Content Daily: Welcome to my little corner of the blockchain

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Links and micro-summaries from my 1000+ daily headlines. I filter them so you don't have to.

First posted on my Steem blog: SteemIt.

1. Steem @kralizec:Liquid Iron Rain - Subtitle: While humanity is currently dealing with the inconvenience of the COVID-19 pandemic an old proverb says “It can always be worse”. And an exoplanet WASP-76b is evidence of this. - This Steem planet tells us about a planet, WASP-76b, that was discovered in 2013. The planet is in close orbit around its star, which makes it exceedingly hot, and it is "tidally locked" in its orbit, meaning that the same side is always facing the center of the orbit. As a result, one side of the planet has a temperature of about 2300 (C) and the other side has a temperature of 2400 (C). When astronomers sought to identify the iron on the planet, they concluded that it's being heated to evaporation on the hotter side and then condensing raining down as a liquid on the cooler side. All in all, the conditions seem inhospitable for life as we know it. (A 10% beneficiary setting has been applied to this post for @kralizec.)


2. Seeing Through Walls - A team led by MIT's Dina Katabi has developed a technique that makes use of machine learning and low power radio frequency (RF) signals to interpret what's happening on the other side of a wall. As the RF signals get bounced around by encountering different surfaces, the AI system can interpret whether people are present, how they are moving, and even the type of activity that they're engaged in. The technique was developed by Tianhong Li and Lijie Fan. Li is quoted as saying, "they can see in the dark. They can see through walls or furniture", and Fan says, "Our goal is to understand what people are doing". Potential uses include safety monitoring in nursing homes or terrorist tracking in stand-off or hostage situations. Katabi notes that, "In living situations, one advantage of monitoring activity through walls with RF signals is that they are unable to resolve faces or see what a person is wearing, for instance, so they could afford more of a sense of privacy than studding the home with cameras". The system makes use of RF frequencies between 5.4 and 7.2 GHZ, which bounce strongly off of humans because our bodies are densely packed with water. Efforts at using RF to see through walls go back at least as far as 2009, but previous solutions did not incorporate the use of artificial intelligence (AI)
   
   Here is a video embed from the article:

   Sounds a lot like passive radar. I have often thought that similar techniques could be used for medical imaging, especially as a tool for first responders.



3. High-Speed Robot Arm Hands Off Package to Delivery Drone - Subtitle: Why land a drone to pick up a package when it can snatch it from a robot arm without stopping? - As researchers learn about urban drone delivery, it's still not clear whether the economic model will ever work, but it is clear that minimizing energy use is important. One of the most energy-expensive phases of drone delivery is the action of dropping off or picking up the cargo. In order to reduce that pain point, Tokyo's Ishikawa Group Laboratory has developed a system that makes use of a hook and robotic arm so that the drone can pick up the cargo in flight, without needing to touch down on the ground. For close range deliveries, less than 1km, simulations suggest that this technique delivers a 65% efficiency improvement. At longer distances, the improvement goes down, but even at 4km, the improvement is still estimated at 18%. Future improvements will upgrade from 2-axis arms to 6-axis arms in order to facilitate self-reloading and speed matching.
   
   Here is a video embed from the article:
   

   In the video, the drone is moving at about 1 meter per second, and the actual hand-off takes approximately 0.3 seconds.



4. Is faster-than-light travel possible? - Recognizing that faster than light travel is equivalent to traveling backwards in time, Sabine Hossenfelder addresses 3 arguments against the possibility of faster than light travel: (i) Einstein's theory of relativity; (ii) The grandfather paradox; and (iii) Quantum mechanics. On the first, she says that the theory of relativity doesn't say anything about whether it's possible to travel faster than light. Instead, she says that it would take an infinite amount of energy to get a sub-light-speed particle moving faster than light. In short, it's not forbidden, but no one knows how to make it happen. On the second, she says that the grandfather paradox only arises when the direction of time is inconsistent. If I go back in time, but I'm getting older at the same time, then time is moving in two directions at once. As long as we insist that the direction of time is consistent, the grandfather paradox doesn't rule out moving backwards in time. On the third point, she says that quantum mechanics suggests that faster than light travel would annihilate the universe, and since the universe exists, time travel must be impossible. She retorts, however, that she thinks quantum mechanics is not a fundamental theory, but an approximation. She suggests, instead, that the idea that time travel would destroy the universe may be due to a misunderstanding of a more fundamental theory.
   
   Here is a video embed from the article:
   

   She closes with this:

   In summary, there is no reason in principle why faster than light travel or faster than light communication is impossible. Maybe we just have not figured out how to do it.



5. Here’s how we could mine the moon for rocket fuel - Subtitle: The Artemis program is supposed to usher in a new age of lunar mining, especially for water ice. But how, exactly? - The moon has a variety of valuable resources including platinum, gold, and rare-earth metals. The one that is most useful, though, is water. Water can be split into hydrogen and oxygen, and when those elements are liquefied, they can be used as rocket fuel. NASA estimates that between 600 million and 1 billion metric tons of water may be available for harvesting. If people learn how to harvest and process that material, the Moon could become a half-way house for travelers on their way to Mars. The challenge, however, is that the water on the Moon is scattered around throughout the soil. The article describes a possible mining technique like this:

   A tent cover over the soil (transparent, so the redirected sunlight could hit the surface) would trap and capture this water vapor, which would be moved into large aluminum units where it would freeze back into ice. Haulers (maybe robotic, or maybe driven by astronauts) would drive the ice out to a facility where it could be purified. Here, the water would be split into hydrogen and oxygen through electrolysis and finally liquefied so the constituents could be used as rocket propellant.

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