Many people think of the James Webb Space Telescope as a sort of Hubble 2. They understand that the Hubble Space Telescope (HST) has served us well but is now old, and overdue for replacement. NASA seems to agree, as they have not sent a maintenance mission in over fifteen years, and are already preparing to wind down operations. But a recent paper argues that this is a mistake. Despite its age, HST still performs extremely well and continues to produce an avalanche of valuable scientific results. And given that JWST was never designed as a replacement for HST — it is an infrared (IR) telescope) — we would best be served by operating both telescopes in tandem, to maximize coverage of all observations.
Let’s not fool ourselves: the Hubble Space Telescope (HST) is old, and is eventually going to fall back to Earth. Although it was designed to be repairable and upgradable, there have been no servicing missions since 2009. Those missions relied on the Space Shuttle, which could capture the telescope and provide a working base for astronauts. Servicing missions could last weeks, and only the Space Shuttle could transport the six astronauts to the telescope and house them for the duration of the mission.
Without those servicing missions, failing components can no longer be replaced, and the overall health of HST will keep declining. If nothing is done, HST will eventually stop working altogether. To avoid it becoming just another piece of space junk, plans are already being developed to de-orbit it and send it crashing into the Pacific Ocean. But that’s no reason to give up on it. It still has as clear a view of the cosmos as ever, and mission scientists are doing an excellent job of working around technical problems as they arise.
The James Webb Space Telescope was launched into space on Christmas dat in 2021. Its system of foldable hexagonal mirrors give it an effective diameter some 2.7 times larger than HST, and it is designed to see down into the mid-IR range. Within months of deployment, it had already seen things that clashed with existing models of how the Universe formed, creating a mini-crisis in some fields and leading unscrupulous news editors to write headlines questioning whether the “Big Bang Theory” was under threat!
This image of NASA’s Hubble Space Telescope was taken on May 19, 2009 after deployment during Servicing Mission 4. NASAThe reason JWST was able to capture such ancient galaxies is that it is primarily an IR telescope: As the Universe expands, photons from distant objects get red-shifted until stars that originally shone in visible light can now only be seen in the IR. But these IR views are proving extremely valuable in other scientific fields apart from cosmology. In fact, many of the most striking images released by JWST’s press team are IR images of familiar objects, revealing hidden complexities that had not been seen before.
This is a key difference between the two telescopes: While HST’s range overlaps slightly with JWST, it can see all the way up into ultraviolet (UV) wavelengths. HST was launched in 1990, seven years late and billions of dollars over budget. Its 2.4 meter primary element needed to be one of the most precisely ground mirrors ever made, because it was intended to be diffraction limited at UV wavelengths. Famously, avoidable problems in the testing process led to it being very precisely figured to a slightly wrong shape, leading to spherical aberration preventing it from coming to sharp focus.
Fortunately the telescope was designed from the start to be serviceable, and even returned to Earth for repairs by the Space Shuttle if necessary. In the end though, NASA opticians were able to design and build a set of corrective optics to solve the problem, and the COSTAR system was installed by astronauts on the first servicing mission. Over the years, NASA sent up three more servicing missions, to upgrade or repair components, and install new instruments.
Illustration of NASA’s James Webb Space Telescope. Credits: NASAHST could be one of the most successful scientific instruments ever built. Since 1990, it has been the subject of approximately 1200 science press releases, each of which was read more than 400 million times. The more than 46,000 scientific papers written using HST data have been cited more than 900,000 times! And even in its current degraded state, it still provided data for 1435 papers in 2023 alone.
JWST also ran over time and over budget, but had a far more successful deployment. Despite having a much larger mirror, with more than six times the collecting area of HST, the entire observatory only weighs half as much as HST. Because of its greater sensitivity, and the fact that it can see ancient light redshifted into IR wavelengths, it can see far deeper into the Universe than HST. It is these observations, of galaxies formed when the Universe was extremely young (100 – 180 million years), that created such excitement shortly after it was deployed.
As valuable as these telescopes are, they will not last forever. JWST is located deep in space, some 1.5 million kilometers from Earth near the L2 Lagrange point. When it eventually fails, it will become just another piece of Solar System debris orbiting the Sun in the vast emptiness of the Solar System. HST, however, is in Low Earth Orbit (LEO), and suffers very slight amounts of drag from the faint outer reaches of the atmosphere. Over time it will gradually lose speed, drifting downwards until it enters the atmosphere proper and crashes to Earth. Because of its size, it will not burn up completely, and large chunks will smash into the surface.
Because it cannot be predicted where exactly it will re-enter, mission planners always intended to capture it with the Space Shuttle and return it to Earth before this happened. Its final resting place was supposed to be in display in a museum, but unfortunately the shuttle program was cancelled. The current plan is to send up an uncrewed rocket which will dock with the telescope (a special attachment was installed on the final servicing mission for this purpose), and deorbit it in a controlled way to ensure that its pieces land safely in the ocean.
You can find the original paper at https://arxiv.org/abs/2410.01187
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On November 26th, 2018, NASA’s Interior Exploration using Seismic Investigations, Geodesy, and Heat Transport (InSight) mission landed on Mars. This was a major milestone in Mars exploration since it was the first time a research station had been deployed to the surface to probe the planet’s interior. One of the most important instruments InSight would use to do this was the Heat Flow and Physical Properties Package (HP3) developed by the German Aerospace Center (DLR). Also known as the Martian Mole, this instrument measured the heat flow from deep inside the planet for four years.
The HP3 was designed to dig up to five meters (~16.5 ft) into the surface to sense heat deeper in Mars’ interior. Unfortunately, the Mole struggled to burrow itself and eventually got just beneath the surface, which was a surprise to scientists. Nevertheless, the Mole gathered considerable data on the daily and seasonal fluctuations below the surface. Analysis of this data by a team from the German Aerospace Center (DLR) has yielded new insight into why Martian soil is so “crusty.” According to their findings, temperatures in the top 40 cm (~16 inches) of the Martian surface lead to the formation of salt films that harden the soil.
The analysis was conducted by a team from the Microgravity User Support Center (MUSC) of the DLR Space Operations and Astronaut Training Institution in Cologne, which is responsible for overseeing the HP3 experiment. The heat data it obtained from the interior could be integral to understanding Mars’s geological evolution and addressing theories about its core region. At present, scientists suspect that geological activity on Mars largely ceased by the late Hesperian period (ca. 3 billion years ago), though there is evidence that lava still flows there today.
The “Mars Mole,” Heat Flow and Physical Properties Package (HP³). Credit: DLRThis was likely caused by Mars’ interior cooling faster due to its lower mass and lower pressure. Scientists theorize that this caused Mars’ outer core to solidify while its inner core became liquid—though this remains an open question. By comparing the subsurface temperatures obtained by InSight to surface temperatures, the DLR team could measure the rate of heat transport in the crust (thermal diffusivity) and thermal conductivity. From this, the density of the Martian soil could be estimated for the first time.
The team determined that the density of the uppermost 30 cm (~12 inches) of soil is comparable to basaltic sand – something that was not anticipated based on orbiter data. This material is common on Earth and is created by weathering volcanic rock rich in iron and magnesium. Beneath this layer, the soil density is comparable to consolidated sand and coarser basalt fragments. Tilman Spohn, the principal investigator of the HP3 experiment at the DLR Institute of Planetary Research, explained in a DLR press release:
“To get an idea of the mechanical properties of the soil, I like to compare it to floral foam, widely used in floristry for flower arrangements. It is a lightweight, highly porous material in which holes are created when plant stems are pressed into it... Over the course of seven Martian days, we measured thermal conductivity and temperature fluctuations at short intervals.
“Additionally, we continuously measured the highest and lowest daily temperatures over the second Martian year. The average temperature over the depth of the 40-centimetre-long thermal probe was minus 56 degrees Celsius (217.5 Kelvin). These records, documenting the temperature curve over daily cycles and seasonal variations, were the first of their kind on Mars.”
NASA’s InSight spacecraft landed in the Elysium Planitia region on Mars on 26 November 2018. Credit: Credit: NASA-JPL/USGS/MOLA/DLRBecause the encrusted Martian soil (aka. “duricrust”) extends to a depth of 20 cm (~8 inches), the Mole managed to penetrate just a little more than 40 cm (~16 inches) – well short of its 5 m (~16.5 ft) objective. Nevertheless, the data obtained at this depth has provided valuable insight into heat transport on Mars. Accordingly, the team found that ground temperatures fluctuated by only 5 to 7 °C (9 to 12.5 °F) during a Martian day, a tiny fraction of the fluctuations observed on the surface—110 to 130 °C (230 to 266 °F).
Seasonally, they noted temperature fluctuation of 13 °C (~23.5 °F) while remaining below the freezing point of water on Mars in the layers near the surface. This demonstrates that the Martian soil is an excellent insulator, significantly reducing the large temperature differences at shallow depths. This influences various physical properties in Martian soil, including elasticity, thermal conductivity, heat capacity, the movement of material within, and the speed at which seismic waves can pass through them.
“Temperature also has a strong influence on chemical reactions occurring in the soil, on the exchange with gas molecules in the atmosphere, and therefore also on potential biological processes regarding possible microbial life on Mars,” said Spohn. “These insights into the properties and strength of the Martian soil are also of particular interest for future human exploration of Mars.”
What was particularly interesting, though, is how the temperature fluctuations enable the formation of salty brines for ten hours a day (when there is sufficient moisture in the atmosphere) in winter and spring. Therefore, the solidification of this brine is the most likely explanation for the duricrust layer beneath the surface. This information could prove very useful as future missions explore Mars and attempt to probe beneath the surface to learn more about the Red Planet’s history.
Further Reading: DLR
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The gravitational field of a rotating black hole is powerful and strange. It is so powerful that it warps space and time back upon itself, and it is so strange that even simple concepts such as motion and rotation are turned on their heads. Understanding how these concepts play out is challenging, but they help astronomers understand how black holes generate such tremendous energy. Take, for example, the concept of frame dragging.
Black holes form when matter collapses to be so dense that spacetime encloses it within an event horizon. This means black holes aren’t physical objects in the way they are used to. They aren’t made of matter, but are rather a gravitational imprint of where matter was. The same is true for the gravitational collapse of rotating matter. When we talk about a rotating black hole, this doesn’t mean the event horizon is spinning like a top, it means that spacetime near the black hole is twisted into a gravitational echo of the once rotating matter. Which is where things get weird.
Suppose you were to drop a ball into a black hole. Not orbiting or rotating, just a simple drop straight down. Rather than falling in a straight line toward the black hole, the path of the ball will shift toward an orbital path as it falls, moving around the black hole ever faster as it gets closer. This effect is known as frame dragging. Part of the “rotation” of the black hole is transferred to the ball, even though the ball is in free fall. The closer the ball is to the black hole, the greater the effect.
This view of the M87 supermassive black hole in polarized light highlights the signature of magnetic fields. (Credit: EHT Collaboration)A recent paper on the arXiv shows how this effect can transfer energy from a black hole’s magnetic field to nearby matter. Black holes are often surrounded by an accretion disk of ionized gas and dust. As the material of the disk orbits the black hole, it can generate a powerful magnetic field, which can superheat the material. While most of the power generated by this magnetic field is caused by the orbital motion, frame dragging can add an extra kick.
Essentially, a black hole’s magnetic field is generated by the bulk motion of the accretion disk. But thanks to frame dragging, the inner portion of the disk moves a bit faster than it should, while the outer portion moves a bit slower. This relative motion between them means that ionized matter moves relative to the magnetic field, creating a kind of dynamo effect. Thanks to frame dragging, the black hole creates more electromagnetic energy than you’d expect. While this effect is small for stellar mass black holes, it is large enough for supermassive black holes that we might see the effect in quasars through gaps in their power spectrum.
Reference: Okamoto, Isao, Toshio Uchida, and Yoogeun Song. “Electromagnetic Energy Extraction in Kerr Black Holes through Frame-Dragging Magnetospheres.” arXiv preprint arXiv:2401.12684 (2024).
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Rongoā Māori is the “indigenous way of healing”: a combination of herbal and spiritual medicine used by the Māori of New Zealand. As The Encyclopedia of New Zealand notes, there were both supernatural and human illnesses, with the former treated through spiritual means (e.g., prayers, dunking in water, and other treatments described below), and the latter through herbal remedies. Here, for example, are the supernatural maladies and remedies:
Mate atua – supernatural illnessesMate atua were supernatural afflictions, sometimes caused by malevolent spirits when a person had broken a tapu (religious restriction). Dealing with mate atua required a tohunga (priest). His first job was to determine the hara (transgression) committed, and to identify the spirit. The tohunga took a thorough case history of all the patient’s actions before they got ill, sometimes including the patient’s and family’s dreams.
A tohunga’s jobTohunga were experts in various fields, including the arts, agriculture, fishing, warfare and healing. They were also seen as the earthly medium of the gods, and were intensively trained in whare wānanga (houses of higher learning). Tohunga held a position of authority and respect, but also had the huge responsibility of keeping their people healthy.
Finding the cause was the first stage of treatment, followed by exorcism of the spirit that had possessed the patient. The next stage was a whakahoro (purificatory rite) to remove the effects of the tapu. This usually involved dipping the patient in a stream while the tohunga performed a karakia (prayer) or incantation.
MariungaThe Ngāti Porou leader Tuta Nihoniho described the mariunga – a wand of wood such as karamū, māpou or maire, which was touched to the body of an invalid and received their essence. It was then taken to a tohunga, who could tell whether the patient would recover.
Takutaku riteAnother rite, the takutaku, involved touching the patient with a karamū leaf, which was then floated downstream. The malevolent spirit would be carried to sea and then to Te Waha o te Parata (a huge whirlpool, caused by a great monster), and finally to the underworld. Freed of the spirit, the patient was then sprinkled with, or immersed in, water.
The site also lists a number of herbal plants used for “human” illnesses, although, as far as I know, none of them have been tested by the gold standard of modern medicine: controlled, randomized, and double-blind testing. I have no doubt that some of these plants do work, but in the absence of testing we won’t really know which ones, and how efficacious they are.
As Wikipedia notes, these forms refer. .
. . . . to the traditional Māori medicinal practices in New Zealand. Rongoā was one of the Māori cultural practices targeted by the Tohunga Suppression Act 1907, until lifted by the Maori Welfare Act 1962. In the later part of the 20th century there was renewed interest in Rongoā as part of a broader Māori renaissance.
Rongoā can involve spiritual, herbal and physical components. Herbal aspects used plants such as harakeke, kawakawa, rātā, koromiko, kōwhai, kūmarahou, mānuka, tētēaweka and rimu.
The practice of Rongoā is only regulated by the Therapeutics Products Bill in the case of commercial or wholesale production so that “Māori will continue using and making rongoā just as they have for generations.”
The Tohunga Suppression Act outlawed traditional medicine in favor of “Western” medicine, but, as the note above shows, the ban lasted just 55 years, and Rongoā Māori is now again legal, though its practitioners often realize that they need to send patients to modern doctors if a traditional cure doesn’t look propitious.
However, there seems to be a move afoot to make Rongoā Māori coequal to modern medicine, if not in curative properties at least in “deep mutual respect.” But, those two items are not independent, for how can a modern physician respect medicines that haven’t been properly tested, much less have any respect for supernatural cures?
What is bad about the attempt to get “deep respect” for indigenous medicine that hasn’t been properly vetted, is that with medicine, unlike with incorporating other indigenous ways of knowing into teaching (e.g., Māātauranga Māori), human lives and health are at stake, so I do have issues with the article below in the ANZ Journal of Surgery (click to read for free).
This study is really an anecdotal one, and with a very small and geographically limited sample, too. The authors recruited four colorectal “Western” surgeons (WS) from the Christchurch region of New Zealand, all of whom had expressed interest in Rongoā Māori (RM). Likewise, the authors recruited seven Rongoā Māori practitioners, four of whom volunteered to be part of the study. Therefore we have a total of eight subjects, all of whom were asked their views about the medicine practiced by the other group. The interviews took place once, and were 30-60 minutes long. The actual study thus lasted a maximum of eight hours.
The upshot:
Western surgeons’ perspectives on RM
The results are no surprise: the doctors didn’t know much about RM. But they were “open to collaboration”, though it wasn’t clear what kind of collaboration. (I can understand that a Māori patient might want a Māori RM practitioner around, at least for solace and cultural comfort.) And of course the doctors thought that, in general, there needs to be better communication between practitioners of modern and of indigenous medicine. Finally, the surgeons cited “systemic barriers, such as bureaucratic hurdles and the absence of clear referral pathways” as impediments to collaboration or “integration”.
Rongoa practitioners’ perspectifes on modern medicine
The indigenous doctors “often feel overlooked within the healthcare system. And this leads to the article’s theme: that modern medicine must be infused in some way with indigenous medicine: a “genuine collaboration”. For instance we read this:
Rongoā practitioners often feel overlooked within the healthcare system. This highlights the need for initiatives that aim to raise the profile of Rongoā Māori within New Zealand’s healthcare system (Table 1). One practitioner mentioned ‘collaboration is minimal, at this stage like the non-Māori community certainly don’t even know that Rongoā exists or anything about it and so that’s not being referred’.
. . . Formulating a genuinely collaborative approach requires recognition of Rongoā Māori as a an option in the patient care journey. ‘Building relationships is key… maybe starting with shared learning experiences,’ one practitioner suggested, proposing foundational steps towards effective collaboration.
. . . . This perspective challenges the healthcare sector to move beyond tokenistic inclusion, advocating for a genuine integration of Rongoā Māori that honours its potential to contribute to improved health outcomes, particularly for Māori patients.
. . . Understanding Rongoā Māori in its full depth requires acknowledging and valuing its comprehensive approach to health, which integrates the spiritual, mental, and physical dimensions of well-being.
The problem here is that we do not know the potential of RM to contributed to improved health outcomes–not without scientific testing of RM remedies, especially the “spiritual” ones. The article refers repeatedly to “mutual respect” of the two types of medicine, as well as the advantage of RM in being “holistic” (presumably meaning it uses spiritual cures as well as medical ones).
The conclusion, which was inevitable, is that modern medicine should collaborate with RM in curing patients. I quote from the paper (bolding is mine):
As identified in the interviews, it is imperative that a curriculum for healthcare professionals encompasses not only the theoretical concepts but also the practical applications of Rongoā Māori. This requires a willingness to move beyond a cursory acknowledgement of Indigenous practices within the medical education system to embedding it as a vital component of healthcare training. It was proposed that an effective educational initiative could take the form of an immersive wānanga on a marae, where tauira (students) and tākuta (doctors) would have the opportunity to learn directly from Rongoā practitioners in a setting that honours the roots of the mātauranga.28–30 In addition to this, incorporating placement based learning would further enable Western practitioners to observe the holistic model of care first hand. This aligns with the insights from the interviews where it was emphasized that Rongoā Māori is dynamic in its practice and does not follow a prescribed regimen.17 By having the opportunity to experience this personalized approach, healthcare professionals can better appreciate the value of nurturing this collaborative relationship.
. . .Recognizing the immense benefits that a holistic model of healthcare offers, there is an unequivocal need to navigate and dismantle the systemic barriers that Rongoā practitioners are faced with. This necessitates a concerted push to ensuring Indigenous healing practices are formally recognized within healthcare frameworks to facilitate a collaborative coexistence with Western medical practices. Moreover, establishing structural support to facilitate funding and infrastructure is an essential component to enhancing the capacity of the current healthcare system to address a diverse range of health needs and allowing this to thrive. It is paramount that this collaboration is guided by Rangatira and Tohunga in this field to ensure the delivery of health services is culturally congruent and responsive. The move towards an inclusive healthcare system that respects the diversity of cultures aligns with Te Tiriti o Waitangi’s principles, honouring Māori sovereignty and self-determination over their health.
“Te Teriti,” of course, is the 1840 Treaty of Waitangi, which made England the sovereign government of New Zealand, conferred on the Māori British citizenship with all the attending rights, and allowed Māori to keep their lands and possessions. But there is nothing about health in that treaty at all, though of course anybody can “self determine” whether they get care, and whether they get RM care, modern medicine, or both. But the Treaty of Waitangi has assumed an almost sacred position in New Zealand culture, now viewed as mandating that all aspects of Māori culture and “ways of knowing” must be considered coequal in the country. Right now there’s a big battle about how far Māori “ways of knowing” are taught as coequal to science in schools, and the indigenous people seem to be winning that fight. This article is just a salvo in the battle for medicinal hegemony.
But before they win the Battle of Medicine, any RM-based cures, whether they be based on plants or supernaturalism, must be tested—and tested according to the best procedures of modern medicine, usually double-blind, randomized, and controlled trials. Without those trials, you simply can’t be sure that a treatment works. Saying “our tradition shows that it works” is not sufficient, nor is the claim “well, it worked for me!” We all know the power of confirmation bias and of the placebo effect, and the kind of testing described above is designed to eliminate these effects. (As Richard Feynman famously said, “You must not fool yourself, and you are the easiest person to fool.”)
So no: there cannot be deep mutual respect between indigenous medicine and modern (aka “Western”) medicine until indigenous treatments are tested according to the standards of Western medicine. It will not work the other way around.
I am heartened that some RM practitioners recognize when herbs and superstition won’t work, and summarily hand their patients over to modern doctors. But I don’t think RM should be integrated with modern medicine, or treated with great respect. Until it’s proven efficacious, the null hypothesis should be that the untested treatments of RM comprise quackery