The discovery of a Martian sarcophagus in Colorado in 1864: An oddball story, or consistent with the lore of the day?
Learn about your ad choices: dovetail.prx.org/ad-choicesIt's not often that astronomers can observe huge changes in a galaxy's brightness over the course of a few years. Most galaxies change in brightness (and other characteristics) over millions or billions of years. So, when images of the 10-billion-light-year distant galaxy J0218-0036 showed that it dimmed down by a twentieth of its previous brightness in just 20 years, observers were surprised. What could cause it to do that? That's not "normal" for AGN.
The ice giant Uranus is one of the most fascinating objects in the solar system, with its sideways rotation, intricate ring system, and unique family of moons. However, it is also one of the least explored objects in the solar system, owing to its extreme distance from the Sun. With NASA’s Voyager 2 spacecraft remaining as the only spacecraft to visit Uranus, scientists continue to design and envision mission concepts for returning to explore Uranus and its icy secrets.
Less than two days from now, NASA’s Artemis II mission is scheduled to lift off for its historic 10-day journey around the Moon, marking the first time humans have ventured beyond Low Earth Orbit for the first time since Apollo 17 in 1972, and possibly even set new distance records for traveling beyond Earth. However, Artemis II is only scheduled as a flyby mission and will not be landing humans on the lunar surface, with this endeavor being scheduled for later missions.
Astronomers studying the ultra-faint dwarf galaxy Pictor II have found an extremely chemically peculiar star that contains traces of elements created by the first stars in the Universe. It's called PicII-503, a "second-generation star" that is one of the most chemically primitive stars ever found.
This collection of images from NASA’s Chandra X-ray Observatory and other telescopes contains regions where stars are forming. Often nicknamed “stellar nurseries,” they are cosmic gardens from which stars – not plants – emerge from the interstellar soil of gas and dust.
Alan Lightman a physicist best known for his writing about science, most famously his 1992 novel Einstein’s Dreams. At present he’s a “professor of the practice of the humanities at MIT.”
Lightman’s recent article in The Atlantic (click headline below or find article archived for frere here), while seeming to buy into the magazine’s recent penchant for osculating religion, really is not. It seems to mostly express a kind of spiritual wonder. But it’s confusing for two reasons.
First, he denies materialism, but latter accepts it (see below).
Second he deals with two forms of dualism: the mind/body dualism dealt with by Descartes, but also a dualism caused by recent advances in medical technology, in which part of your body is not made of tissue (examples are artificial hearts and mind/electrode interfaces) making people part human, part machine.
After reading the piece, I wasn’t sure what the point was except to mirror Lightman’s wonder at the world and his unanswered questions.
It began when Lightman had a colonoscopy, which got him wondering what was going on inside himself; as he said, “I felt like a trespasser in my own body.” And that gets him into the first form of dualism. All bolding henceforth is mine:
Modern neuroscience has largely overthrown the classical view that the mind and the body are fundamentally different substances, and it has shown that all of our thoughts and mental experiences are rooted in the material brain. But even granting that scientific view, there remains a profound disconnect between our conscious self-awareness—rooted in the three pounds of gooey stuff in our skulls—and the rest of our body.
And here’s the confusing bit, where he denies materialism: he simply has to be more than just the substance of his body. Bolding is mine:
After that unsettling medical adventure, I began mulling over why I was so disturbed to see the insides of my body. A number of issues come to mind. For starters, the experience struck me as a vivid demonstration of my materiality. Even though I am a scientist and have a materialist view of the world, I still harbor the belief that I am more than just a jumble of tissues and nerves. The experience of consciousness and life is so sublime that it is hard to imagine it all arising from mere atoms and molecules.
This seems like a case of cognitive dissonance, but it’s not clear whether he really believes what’s in bold as opposed to “harboring” that belief. Yes, we don’t know how consciousness works, but what else is there to create it except the stuff of our bodies and brains? For other people, like Ross Douthat, a failure to understand is by default evidence for god, but nobody who knows the history of science would think that.
Lightman then muses for a while about our failure to fully understand our own bodies, but what is a source of puzzlement to him is a challenge to scientists. We have never made progress in understanding nature by assuming that naturalism is wrong, and so the program to understand consciousness must begin with a naturalistic program—until we find an exception to naturalism!
But later on, Lightman says that he’s really a materialist:
I must again confess that I am a materialist. I respect the belief in an immortal soul. I respect the belief in a nonphysical mind. But, despite my predilection for some transcendent element, I do not share those beliefs. Still, I am baffled by the disconnect I feel between body and mind. I look down at my bare feet and command my toes to wiggle. And they wiggle. But “I” am looking down at them from above. My toes are things that I gaze at from some distance. But what distance? The distance from the camera of my eyes? The distance from my conscious mind, which has these thoughts? And my toes are visible. The inside of my body is even more distant.
Once again his source of wonder is his victimization by an illusion, one described so clearly by Dan Dennett, that there is an “Alan Lightman” sitting somewhere in his brain, a little homunculus that looks down on his toes. Again, he’s baffled, while a biologist would see a challenge. My own view, and I’m no expert, is that the “hard problem of consciousness” will simply devolve to a problem of what brain connections are necessary for the sensation consciousness, and then we’ll have to say, “And that is all we know.”
Finally, having confessed his bafflement, Lightman goes on to describe some medical advances that truly are amazing, but, like the one below, must surely have a naturalistic explanation:
In 2013, scientists at the California Institute of Technology and the University of Southern California implanted two computer chips in the brain of Erik Sorto, then 32, who was paralyzed from the neck down from a gunshot wound. The output from the chips is connected to a computer, which interprets the patterns of their electrical activity; the computer, in turn, is connected to a robot arm. When Sorto is thirsty and merely thinks about reaching for a cup of water, the computer chips in his brain sense his desire and relay that thought to the computer, and the robot arm grabs a cup of water and brings it to his lips. When I interviewed Sorto in November 2021 and asked him what it felt like to have this machine in his body, he said that he felt mostly human but also part cyborg.
Now that is amazing, especially because, as far as I know, the way it works was not designed from first principles, although some knowledge of neuroscience was surely required (where do you put the chips?). But this surely has a naturalistic explanation, unless you think that god did it or some fundamental principles of how neurons and muscles work has eluded us.
And that’s pretty much it. I may have failed to be impressed simply because I’m jaded, and as a scientist I’m used to unsolved problems that to other conjure up spiritual or even non-naturalistic explanations. But still, I wonder why The Atlantic published this.
As we anticipate the Artemis II launch, now slated for early April with plans to take four astronauts on a trip around the Moon and back to Earth, NASA has been unveiling some significant changes to its plans for returning to the Moon and beyond. If you have fallen behind these announcements, here is a summary of the important bits.
Artemis II will continue as planned, marking the first crewed deep space mission since 1972 (Apollos 17). The original plan was for Artemis III to land on the Moon in 2027, but this mission has been pushed to an Artemis IV mission in 2028. A new Artemis III mission has been inserted – this will go only to low Earth orbit (LEO) and will test the integration of all the systems necessary to land on the Moon. This will include docking with one or both of the two landers, one being built by SpaceX and one by Blue Origin. This sounds like a really good idea, and it did seem unusual that they were planning on going straight to the Moon without ever test docking with the lander.
Even though landing on the Moon will be delayed by at least a year, NASA says this will set them up to have at least annual landings on the Moon after that, with a goal of a landing every six months. The reason for this frequent pace is the the more recent announcement by NASA last week – that they are putting on pause plans for a Lunar Gateway in lunar orbit and instead are going to focus on building a permanent Moon base near the lunar south pole.
In order to make this possible, and to support the future Moon base (no word yet on whether this will be called Moon Base Alpha, as it should) NASA plans about 30 uncrewed robotic landings on the Moon every year. They will be scoping out the location for the base and delivering equipment and supplies.
What about the Space Launch System (SLS)? When hearing these plans one of my first questions was – are they going to do this all with the SLS? Each SLS launch costs $4.1 billion, with the cost of the single-use ship itself being $2.2-2.5 billion. This is one of the biggest criticisms of the SLS system – they are designed as single-use rockets. Meanwhile, the rocket industry has moved on to reusable rockets, which dramatically reduces the cost. As of now, NASA has approved SLS launches through Artemis V. After that they have not committed to a specific plan. But – they have stated that their goal is to transition to “commercial hardware.” This almost certainly means SpaceX and Starship. I guess they cannot fully commit because Starship is still in development. But if it is ready in time, it seems likely NASA will start relying on Starships to get to the Moon.
This makes a lot of sense. SpaceX’s lander is really a modified Starship – it is stripped of anything it needs to land back on the Earth and is optimized for landing on the airless lunar surface. So – why go all the way to the Moon then dock with a Starship lander to land on the Moon. Why not just dock with the Starship in LEO then take the lunar-modified Starship all the to the Moon and then down to the lunar surface? That seems to be what NASA is planning. For now they will use the SLS to get into LEO, then go the rest of the way on a modified Starship. After Artemis V they may take one Starship into LEO and another to the Moon. They are not fully committing to SpaceX because they don’t want to give them a de-facto monopoly, so the door is open for other companies to compete for this service.
The apparent plans are for the base to be on the surface near the south pole. NASA has been investigating lunar lava tubes as a potential location for a moon base, but there are not identified sites or specific plans right now. This means the surface base will have to be heavily shielded. Perhaps the permanent presence will allow them to build a future base inside a lava tube, which would be much better protected from radiation and micrometeors.
Once all this is worked out, and we have a lunar base serviced by a system to frequently land crew on the surface and return them to Earth, NASA plans to use that lunar base as a stepping stone to Mars. This makes great sense. Remember – 90% of the energy you need to get anywhere in the solar system you expend just getting into LEO. Getting off the lunar surface is relatively easy. This means that a lunar base is an excellent platform from which to launch ships throughout the solar system, including Mars. A ship launching from the Moon can use most of its fuel getting to Mars faster, by spending more of that fuel accelerating to Mars then decelerating to insert into Martian orbit. This is critical because getting to Mars fast is the best defense against radiation exposure by the astronauts.
Along those lines NASA has also announced their plans to use nuclear power in space. This has two components – the first is using nuclear power for the Moon base itself. This is a great idea because you do not want to rely on fuel, which is expensive to ship to the Moon. Solar power on the Moon can be great, but you only see sunlight half the time. This is actually part of the reason to build the base at the south pole, where there are high peak regions that see sunlight 90% of the time. That will likely be an important source of power for the base. The other reason is that the poles also have deep craters that see light 0% of the time, which means there may be some frozen water there, which can be mined as a resource of the base. But even 90% sunlight still means 2-3 days with no sun, which would require significant battery backup. This is fine, but a mini nuclear plant (like the kind of thing you would have on a nuclear submarine) could provide years of reliable power for a lunar base.
The second use of nuclear power in space is for their planned nuclear electric propulsion spaceship. NASA plans for Space Reactor-1 (SR-1) Freedom, a ship propelled by a nuclear electric engine, to be launched in 2028. Nuclear propulsion has been long anticipated, and honestly we should have developed it long ago. This gets beyond the limits of chemical propulsion, and would cut the travel time to Mars. SR-1 Freedom will fly to Mars, and take 1 year to get there. This trip is optimized for efficiency, not speed, as it is a test mission. Once mature it is estimated that nuclear propulsion will reduce a typical trip to Mars from 7-9 months down to 3-4 months, with a theoretical advanced system getting to Mars in 45 days. Now we’re talking.
This also relates to why a lunar base is so important to Mars missions. Nuclear engines are efficient, but do not have the thrust to launch from Earth’s surface into orbit. You would have to launch any such vehicle with chemical fuel then switch to nuclear for the trip to Mars. But – if you are already on the lunar surface, you still need chemical rockets, but only small boosters rather than something the size of SLS or Starship.
Taking all of this into account, it really does seem that NASA has a well-thought out plan for developing the infrastructure to maintain a presence on the Moon and for missions to Mars (and potentially other solar system destinations). This is much better than the one-off (so-called flags and footprints) missions of the past. Honestly, this is what I naively expected would happen back in the 1970s or 80s to follow up the Apollo missions. It took 50 years longer than expected, but it’s good to see happening now. I know not everyone agrees with the priority of sending any people into space, and would rather have an entirely robotic space program, but that is a discussion for another day.
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