A while back, I released a post made up of updates to previous posts as news updates came out about them. Since the news has continued to update itself, here is part two of that. I would encourage you to re-read the previous posts, which I have linked.
2024 Solar Storm
A few months ago, I wrote a post about Solar Storms and how they affect the planet. That was at the beginning of the solar maximum, when the frequency of solar storms increases every eleven years. We are currently further into the solar maximum, so we are experiencing even more storms. At time of writing, we are in the middle of the largest solar storm in over twenty years caused by an ongoing coronal mass ejection. Perhaps the most obvious sign of the ongoing storm is the fact that aurora borealis (and aurora australis) have occurred at far lower latitudes than normal, with sightings documented in Mexico and even Northern India. Remember, auroras are caused by charged particles in these solar storms hitting the Earth’s atmosphere. As these particles slow down from moving through air, their energy gets converted into light. Because these particles have an electric charge, their paths can be redirected along the Earth’s magnetic field. This is why auroras are normally only visible from the Arctic and Antarctic as these regions are where Earth’s magnetic field intersects with Earth’s atmosphere. But during these coronal mass ejections, a larger volume of even faster moving particles are emitted. Their speed makes them harder to deflect and their number makes it more likely that some get through the field. As such, stronger solar storms result in auroras at lower altitudes than normal.
Fortunately, the threat posed by this storm is so far minimal. The intensity of these storms is measured by how much they deform Earth’s magnetic field, measured in nanoTeslas. At time of writing, this storm has peaked at -412 nT.* For comparison, the 2003 solar storm maxed out at -422 nT, the 1989 storm that caused the Quebec blackout peaked at -589 nT, and the Carrington event is estimated to have peaked somewhere between -800 and -1750 nT. This storm, while very notable, is still smaller than other storms we’ve weathered. So far, power grids around the world have been able to manage the stresses put on them without any major blackouts. Radio communications and satellite infrastructure have also seen some disruption, but no significant impacts have been reported. While much of this is down to the storm not being as severe as it could be, some of it is because we’ve gotten better at protecting our electrical and communications infrastructure from these storms. It will be interesting (or existentially terrifying) to see how we fare against something the size of the Quebec storm, but I’m optimistic. At the very least, the skies are pretty at the moment.
(Note; since writing this section, this solar storm has since ended, running its course from May 10th to 13th. I did not get a chance to see it due to it being cloudy where I lived. I am nonplussed.)
New Gene Therapy
A few months ago, I wrote about Genetic Disorders and ended with the potential for treatment using gene therapy. Years before that, I wrote about CRISPR, an emerging technology that can bring such treatments closer to our grasp. Well, a few months ago, the FDA approved the very first CRISPR-based gene therapy. The therapy, called Casgevy, is designed to treat sickle cell disease.
Red blood cells contain a protein called hemoglobin which binds to oxygen and transports it to other cells. In healthy cells, these hemoglobin proteins are free-floating and the cell itself is a flexible, round disc shape. In patients with sickle cell disease, a mutation results in hemoglobin proteins that stick to each other to produce a long, stiff fiber. Having these fibers inside it distorts the blood cell into a long, rigid sickle shape.** These sickle cells are less elastic, so they get caught in narrow blood vessels and cause chronic pain, inflammation, infarction, and even stroke. Anemia is caused by misshapen cells dying faster than they can be replaced and these sickle cells can damage other organs and tissues as they move through them, causing infection (damage to the spleen), kidney disease, gallstones, and blindness. Historically, the most that could be done for patients has been symptom management. Blood transfusions are used during the worst episodes of pain and hypoxia, but this only offers temporary relief. Bone marrow transplants have proven to be a permanent solution (more on why in a minute), but this only works if the donor is a close relative.
The new therapy is meant to treat severe sickle cell anemia as well as other hemoglobin disorders. A sample of the patient’s bone marrow (where blood comes from) is extracted and is modified using CRISPR.*** This modified bone marrow won’t produce sickle cells, but it is otherwise genetically identical to the patient so it won’t be rejected by the patient’s immune system. The patient then receives high-dose chemotherapy to kill off all their existing bone marrow before re-transplanting the genetically modified bone marrow, which then reproduces to become the patient's new bone marrow (there are other diseases where killing off the bone marrow is standard practice, such as for certain blood cancers). The original clinical trial saw no patients reject their new bone marrow with over 90% seeing the disappearance of all severe sickle cell symptoms.
There are still a ways to go for gene therapy in general and CRISPR-based therapies in particular. As mentioned, CRISPR is still far better at removing faulty genes than it is at inserting new genes, which would be necessary for the treatment of most genetic disorders. And sickle cell disease is one of only a few diseases that can be treated in vitro, meaning the affected tissue can be removed from the body, modified in a lab setting, and then reinserted to replace the original tissue. To treat the majority of genetic disorders, we would have to find a safe and reliable way to modify all the affected cells in the body while they’re still inside the patient. But there are studies being done on methods to fix both of these problems, so this will certainly be the first of many such gene therapies.
Fusion Fuels and the Moon
This is a weird one. Over a year ago, I wrote about Artemis and the Moon Missions, where I talked about how an interest of the missions were finding and exploiting lunar resources. I mentioned here that, “lunar regolith (moon dust) contains trace amounts of Helium-3, an isotope of helium that some have proposed could be used as a fuel for fusion reactors (a topic for future posts).” A few months later, I did a post on Fusion and the Latest Breakthrough, where I did not have room to mention this connection. I will rectify this now.
In my post on fusion, I briefly touched on the choice of fuel for fusion reactors and how that is a research topic and source of complication in and of itself. Different elements and isotopes are easier to fuse, produce more energy when fused, and are more readily available. Most experimental reactors today are fueled by Hydrogen-2 (one proton, one neutron) and Hydrogen-3 (one proton, two neutrons). Both fuels are relatively easy to acquire (H-2 can be filtered out of seawater and H-3 is produced by certain nuclear reactions, which could be produced by the fusion reactor itself) and fuses at a relatively low temperature (only a few hundred million degrees). One of the problems H2-H3 fusion has though is that the energy it produces comes in the form of high-energy neutron radiation. The waste products of fusion are still non-radioactive helium, so the only risk would be to those inside the reactor while it’s running (who frankly have much bigger problems). But this radiation would over time damage the components and materials of the reactor while also being more difficult to get energy from. Most designs for such reactors involve lining them with radiation shielding materials that are heated up by the radiation which then have water pumped through them to turn into steam to turn turbines, which would work but would be harder to build and maintain.
Helium-3 is a fusion fuel that, when reacted with H-2, produces energy which comes in the form of high energy protons. Since protons have an electric charge unlike neutrons, they can be blocked by relatively little shielding (aluminum foil vs multiple feet of lead) and can be used to produce electricity directly. The biggest downside to He-3 as a fusion fuel is that there is basically none of it on Earth. Helium is extremely light and only ever found in nature as a gas, so whatever helium our atmosphere held in its youth has long since risen to the uppermost layers and been blown off by solar winds. What helium we have was the waste products of nuclear decay in the Earth’s mantle, which exclusively produces helium-4. If you want He-3, you have to leave Earth. The Sun produces a lot of He-3 as solar wind, and those particles stick to the regolith of atmosphere-less worlds like the Moon. There are estimated to be a million tons of He-3 embedded in the Moon’s dust, enough to power the planet for thousands of years, with more being continuously delivered by solar wind.
Research is ongoing into the economics of extracting He3 from lunar regolith. Most designs involve large vehicles that suck up dust as they travel, heat it up to extract and collect He-3, and dump the depleted dust back where it was found. Many futurists have proposed this to be the future of energy production, but there are skeptics. He-3 is approximated to max out at 50 parts per billion in lunar dust, meaning you’d need to sift through 150 tonnes of regolith to collect one gram of He-3. Put another way, if we could somehow build perfectly efficient fusion reactors that could turn all the theoretical energy produced by fusion into usable electricity, powering every home in the United States would require sifting through roughly 15 square kilometers (5.63 square miles) per day. While theoretically possible, I personally believe that if one wanted to extract energy from the Moon, solar farms built from lunar materials would probably be a more efficient use of your time.
That’s not to say that helium-3 mining wouldn’t be worth doing. Having ready access to such a useful fusion fuel would be of tremendous benefit for fusion research. That research could theoretically translate to applications for fusion reactors that use most accessible fuels. And there are other sources of He-3 in our solar system; the gas giants hold tremendous amounts of helium in their atmospheres and a significant portion of that would be helium-3. Extracting it would be a significant engineering undertaking and likely not feasible in the near-future, but it might be technologically easier than fusion itself. Regardless of if we can turn lunar He-3 into a feasible fuel source, we will benefit tremendously from the research and the access to space that lunar exploration will grant us.
This review was more optimistic than the last one. That’s nice.
For More Details
*These numbers are always negative because they’re the measure of how much the Earth’s magnetic field strength has been weakened by the storm. The further this number is from zero, the worse the storm.
**Not all blood cells in a patient’s body will be sickle cells. The mutant hemoglobin can behave normally, but will start binding to itself during periods of stress, dehydration, high altitude, and temperature swings. Once a blood cell has become a sickle cell, it generally can’t be turned back. Symptom management for sickle cell patients includes controlling for the conditions that cause sickle cells to form.
***This modification takes the form of switching back on fetal hemoglobin. You see, humans produce a slightly different variant of hemoglobin before birth due to the different oxygenation needs in the womb. By age 2, one has completely switched from producing fetal hemoglobin to adult hemoglobin, which is the version of hemoglobin that is mutated in sickle cell patients. Casgevy breaks the gene that switches fetal hemoglobin off, so one starts producing fetal hemoglobin again. As I’ve said before, CRISPR is currently better at removing genes than inserting new ones, hence this strategy. Fetal hemoglobin isn’t ideal for adults, but it’s far better than sickle cell disease.
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