As an historic solar minimum approaches, space radiation becoming more hazardous

UNH researchers find space radiation is increasingly more hazardous

From the UNIVERSITY OF NEW HAMPSHIRE

DURHAM, N.H. – It might sound like something from a science fiction plot – astronauts traveling into deep space being bombarded by cosmic rays – but radiation exposure is science fact. As future missions look to travel back to the moon or even to Mars, new research from the University of New Hampshire’s Space Science Center cautions that the exposure to radiation is much higher than previously thought and could have serious implications on both astronauts and satellite technology.

“The radiation dose rates from measurements obtained over the last four years exceeded trends from previous solar cycles by at least 30 percent, showing that the radiation environment is getting far more intense,” said Nathan Schwadron, professor of physics and lead author of the study. “These particle radiation conditions present important environmental factors for space travel and space weather, and must be carefully studied and accounted for in the planning and design of future missions to the moon, Mars, asteroids and beyond.”

In their study, recently published in the journal Space Weather, the researchers found that large fluxes in Galactic Cosmic Rays (GCR) are rising faster and are on path to exceed any other recorded time in the space age. They also point out that one of the most significant Solar Energetic Particle (SEP) events happened in September 2017 releasing large doses of radiation that could pose significant risk to both humans and satellites. Unshielded astronauts could experience acute effects like radiation sickness or more serious long-term health issues like cancer and organ damage, including to the heart, brain, and central nervous system.

In 2014, Schwadron and his team predicted around a 20 percent increase in radiation dose rates from one solar minimum to the next. Four years later, their newest research shows current conditions exceed their predictions by about 10 percent, showing the radiation environment is worsening even more than expected.

“We now know that the radiation environment of deep space that we could send human crews into at this point is quite different compared to that of previous crewed missions to the moon,” says Schwadron.

The authors used data from CRaTER on NASA’s Lunar Reconnaissance Orbiter (LRO). Lunar observations (and other space-based observations) show that GCR radiation doses are rising faster than previously thought. Researchers point to the abnormally long period of the recent quieting of solar activity. In contrast, an active sun has frequent sunspots, which can intensify the sun’s magnetic field. That magnetic field is then dragged out through the solar system by the solar wind and deflects galactic cosmic rays away from the solar system – and from any astronauts in transit.

For most of the space age, the sun’s activity ebbed and flowed like clockwork in 11-year cycles, with six- to eight-year lulls in activity, called solar minimum, followed by two- to three-year periods when the sun is more active. However, starting around 2006, scientists observed the longest solar minimum and weakest solar activity observed during the space age.

Despite this overall reduction, the September 2017 solar eruptions produced episodes of significant Solar Particle Events and associated radiation caused by particle acceleration by successive, magnetically well-connected coronal mass ejections. The researchers conclude that the radiation environment continues to pose significant hazards associated both with historically large galactic cosmic ray fluxes and large but isolated SEP events, which still challenge space weather prediction capabilities.

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The paper: https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2017SW001803

Update on the worsening particle radiation environment observed by CRaTER and implications for future human deep‐space exploration

Abstract

Over the last decade, the solar wind has exhibited low densities and magnetic field strengths, representing anomalous states that have never been observed during the space age. As discussed by Schwadron et al. (2014a), the cycle 23–24 solar activity led to the longest solar minimum in more than 80 years and continued into the “mini” solar maximum of cycle 24. During this weak activity, we observed galactic cosmic ray fluxes that exceeded the levels observed throughout the space age, and we observed small solar energetic particle events. Here, we provide an update to the Schwadron et al (2014a) observations from the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) on the Lunar Reconnaissance Orbiter (LRO). The Schwadron et al. (2014a) study examined the evolution of the interplanetary magnetic field, and utilized a previously published study by Goelzer et al. (2013) projecting out the interplanetary magnetic field strength based on the evolution of sunspots as a proxy for the rate that the Sun releases coronal mass ejections (CMEs). This led to a projection of dose rates from galactic cosmic rays on the lunar surface, which suggested a ∼20% increase of dose rates from one solar minimum to the next, and indicated that the radiation environment in space may be a worsening factor important for consideration in future planning of human space exploration. We compare the predictions of Schwadron et al. (2014a) with the actual dose rates observed by CRaTER in the last 4 years. The observed dose rates exceed the predictions by ∼10%, showing that the radiation environment is worsening more rapidly than previously estimated. Much of this increase is attributable to relatively low‐energy ions, which can be effectively shielded. Despite the continued paucity of solar activity, one of the hardest solar events in almost a decade occurred in Sept 2017 after more than a year of all‐clear periods. These particle radiation conditions present important issues that must be carefully studied and accounted for in the planning and design of future missions (to the Moon, Mars, asteroids and beyond)

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130 thoughts on “As an historic solar minimum approaches, space radiation becoming more hazardous

  1. Ok. Complete neophyte on solar theory here. Are they saying that there is an inverse relationship between the number of sunspots and the rate and/or strength of CMEs? Please be kind!

    • As our sun becomes less active (solar minimum) it puts out much less solar wind that curbs galactic radiation from entering our solar system. I believe they are thus referring to galactic radiation, not our sun’s.

    • Some of the most powerful CMEs recorded occurred well past solar maximum during the deep into the descent to solar minimum. Coronal holes become more frequent during the descent to minimum (where we are today). Coronal holes (CHs) are associated with ‘open’ magnetic field lines and are often found at the sun’s poles, but can be anywhere on the sun’s disc. Equatorial holes allow an enhanced fast flow of particles to be carried away with the solar wind in the direction of the ecliptic (where the planets are). A CME that eruptsnear areas of open magnetic fields lines is not bent back down to the surface but its trajectory is altered as it continues to flow outward at high velocity.
      Why is not clear. Leif may have some perspective on that. (see more below)
      Of recent note is the so-called Solar Storm of 2012. A Carrington-level CME event occurred in July 2012, with the exception that it did not strike the Earth like the actual Carrington Event of 1859 did. But both the 2012 and the 1859 CME’s occurred during the front-side ascending phase of their respective solar cycle’s climb to cycle maximum.
      https://en.wikipedia.org/wiki/Solar_storm_of_2012
      Here is what the sun looked like exactly 2 solar rotations before the 2012 event.
      https://www.nasa.gov/sites/default/files/styles/full_width_feature/public/images/656133main_coronalhole_sdo_blank_full.jpg
      Note the large Coronal hole that was equatorial as well as very magnetic active regions. As an aside this is NASA’s favorite “Big Bird” coronal hole.
      Right now the sun’s disc facing Earth has both polar and smaller equatorial coronal holes.
      https://sdo.gsfc.nasa.gov/assets/img/latest/latest_512_0193.jpg
      A study published in 2008 found:

      “The primary result of this study is that the trajectory of CMEs is significantly affected when the eruptions occur in close proximity to CHs. The CH acts as a magnetic wall that constrains the CME propagation. CHs are the only large‐scale magnetic features (with a scale size similar to that of CMEs near the Sun) that contain different magnetic, physical and flow properties than the active region corona where CMEs originate.”
      source:
      CME interactions with coronal holes and their interplanetary consequences
      N. Gopalswamy, P. Mäkelä, H. Xie, S. Akiyama, S. Yashiro
      First published: 26 March 2009
      https://doi.org/10.1029/2008JA013686
      or
      https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2008JA013686

      • I’ve often wondered why active regions seem to very often border coronal holes, particularly during low activity periods. I should pose that question to Dr. S., actually.

      • Yes, you should.
        Keep in mind both (CMEs and CHs) are coronal features. Sunspots and associated faculae are surface (photosphere) phenomenon.

    • They have conflated two different things, which makes the paper difficult to follow.
      (a) Lower solar activity, for which fewer sunspots is an indicator, leads to higher GCRs (Galactic Cosmic Rays). GCRs come from the galaxy outside the solar system, and are dangerous for astronauts. Solar activity shields Earth from GCRs, so periods of low solar activity are dangerous for astronauts. I think I am right in saying that the space program of the 1960s got lucky, as there was quite high solar activity then, but they still put a lot of effort then into predicting GCRs and protecting from them.
      (b) Bursts of high solar activity, such as CMEs, are dangerous in their own right. They tend to be very short lived.

      • The Apollo program was specifically timed because they knew the solar max SC 20 timing would open up a window of lower radiation exposure for the astronauts.
        When President Kennedy made his speech about sending men to the Moon by the end of the decade, the engineers had already told him that technically they could do it if they got funding, and that they could do it by the end of the decade to coincide with SC 20 max.
        Besides timing the solar maximum, NASA also employed other strategies for the astronauts to lower their radiation exposure.
        – They avoided the inner Van Allen Radiation belt by highly inclined trajectory. And for the higher altitude outer Van Allenradiation belt they used high speed to minimize their time in the belt.
        – During the lunar cruise phase, the astronauts minimized and/or avoided spending anytime in the thin-skinned/unshielded lunar lander module. The two astronauts who went to the lunar surface on each mission endured much higher radiation exposures than the guy who stayed above in the orbiting command module.
        – Apollo 13 astronauts were subjected to much higher radiation levels because they had to spend almost 4 days in the lunar lander module, using it as their life boat, after the command module had its infamous oxygen tank rupture (and not enough electrical power to be able to stay in it, not for a lack of usable oxygen).
        – Apollo 13 astronaut Jack Swigert died of an unusual cancer at the age of 51 just 12 years after the 1970 ill-fated mission.

      • Bigger, chunkier bits of silicon in the chips in the old electronics would have helped. Not luck so much.

  2. It’s going to be very interesting to see how this all plays out. This applies to all kinds of natural occurring phenomenon, from weather to climate to ocean cycles to geologic events. It may mean a lot or nothing, but we have a front row seat to see it.
    At least we have a lot more tools orbiting the Earth and Sun to record such happenings. Let’s just hope a giant solar blast doesn’t take out all our tools!

    • According to some people that 0.015 drop in TSI can’t have much effect on anything on Earth. So the evidence can be dismissed.

    • We suggest the physical mechanism which explainshow the magnetic field of the Earth can affect the spatial distribution and temporal variations of the surfaceair temperature. The process starts with geomagneticmodulation of the intensity and the depth of penetration of energetic particles into the Earth’s atmosphere,which initiates the ion–molecular reactions affectingthe ozone concentration close to the tropopause. Thisheight level in the Northern Hemisphere is markedwith the maximal absorption of GCRs, where suitableconditions favoring autocatalytic production of O3 inthe Northern Hemisphere, have been found. The variations in the ozone density close to the tropopauseaffect the temperature in the UTLS region due to thehigh absorption capability of O3. The higher the temperature in this region the drier this layer becomes(due to the reduced static stability of the upper troposphere). Vice versa, the cooling of the UTLS regionfacilitates the upward propagation of water vapor.These small fluctuations of humidity in the UTLSregion in winter (north of 40° N) affect the radiationbalance (through the greenhouse effect) and, as a consequence, the surface air temperature.Certainly, this mechanism needs further testing ofits applicability and does not claim to account for allthe possible causal relations and regional features. Wenote that the obtained results are valid for winter, whenthe upper troposphere is much drier. Nevertheless, therelationship between the climate and geomagneticfield is, in our opinion, quite feasible, and its changesshould also be factored into the longterm climaticmodels as one of the climate control
      Geomagnetic Field and Climate: Causal Relations with Some Atmospheric Variables (PDF Download Available). Available from: https://www.researchgate.net/publication/281441974_Geomagnetic_Field_and_Climate_Causal_Relations_with_Some_Atmospheric_Variables [accessed Mar 18 2018].

  3. Well. I told you so. There is a clear reason. Less magnetic field strength means more of the most energetic particles able to escape. Lucky we have the atmosphere protecting us forming O3, NxOx and HxOx.
    Hence. Dont go to the moon or Mars…

    • Unsurprising. There is genetics (the double helix genetic DNA code, only slowly mutable) that explains Darwin, and then the only recently discovered epigenetics (based on methylation and refolding, chnaging relative gene expression, meaning Larmarckian evolution is also possible). The identical twins have (except for accumulated slow random mutations) identical DNA. But after a year in space, the epigenetics changed enough to be significantly measurable in the space station twin. This is a BIG deal. In climate, speaks for example to coral reef adaptability beyond symbiont bleaching/exchange. See my guest post over at Judiths on the ag revolution. Turns out most of the distinct mesoamerican beans (red, black, pinto, navy,…) are derived from one ancestor plant with minimal DNA shifts (nothing more than expected by time since first cultivation). The obvious differences are ‘all’ epigenetics. Wow!

      • Actually, a little research on this matter shows that by the time identical twins are 50, their DNA is no longer identical, no ride in space required.

      • ” Expression of a gene does not change the actual information in said gene.”
        While your statement is true at face value, the end results can depend on the genes that are damaged and either suppressed or expressed through expression switches.
        Radiation can damage DNA. DNA is “repaired” through a complex series of proteins and RNA, all built from the existing DNA. If DNA becomes too damaged, the cell will often just commit suicide (self destruct called apoptosis). Otherwise, the available mechanisms will do their best to repair the DNA to its original coding. But errors can and do occur, so that the original gene is changed. This can lead to all sorts of disease depending on the importance of the gene, and how many copies of it exist in the DNA.
        There are several mechanisms where exposure to radiation could actually result in a change to the genes themselves. In reference to your statement at the beginning, if the DNA that supports the DNA repair is damaged or its expression depressed, damaged DNA cannot be effectively repaired – or If the repair mechanisms make a mistake, the gene appears repaired but is different – likely no longer useful. So the shut-off of a repair gene could result in other genes not being effectively repaired.
        The most common mechanism in gene expression between identical twins DNA is through methylation and similar gene expression switches, but there will be some actual DNA changes over time as well. Radiation exposure speeds up the rate of change, and more change means more chances for errors to accumulate.
        Whether this is enough to be measurable (with some degree of confidence) in this case is not clear to me, but given enough radiation and enough time DNA will drift from the original blueprints by measurable amounts.

      • Latitude March 17, 2018 at 5:41 pm
        guys….that was more fake news from CNN

        No the CNN report was correct it was the NBC one that was wrong.

    • 🙂 How typical. Saw the alarmist headlines. Instead of issuing a correction, the local public BC just updated their title later on.

  4. Radiation is a very big concern for manned space. Our craft are limited in mass, and radiation shielding requires mass to absorb the energy. So we gamble and try to predict the storms. The Moon is realistically 3 days away, You could get there faster with more energy, but then only need even more to slow down so you don’t just fly on past. Coincidentally it takes about 3 days for a CME to reach Earth. So If one were spotted at launch, conceivably the astronauts could be safely protected at a lunar base.
    Longer voyages will come with greater peril. It is akin to the first transoceanic voyages exposed to violent storms while traveling in modest craft. Safe havens are few and far between.
    Magellan never made it around the globe.

    • Well… not to be too nit picky, but Magellan didn’t make it because he died fighting off some angry natives while the rest of his crew fled to the ship.
      Currently there’s no analogue to that in the star ocean.

      • Reminds me of the standard psychology question: –
        Captain Cook (R.N.) started three voyages around the world. He was killed on one. Which one?
        Auto

      • Magellan encountered numerous natives in his travels. While traversing the tip of South America, he encountered the only known tribe of exclusively heterosexual people on the planet. To this day, they are known as the Straights of Magellan.

    • As I recall Ferdinand had on a previous voyage traveled EAST to the area where he was killed on his epic WEST voyage. So it can be said that he was the first to travel round the world.

    • The most dangerous CME’s (the most energetic) can make the 1 AU trip in around 18-24 hours. Maybe even 12-14 hours. ooops.

  5. Climate formation processes have been considered as depending on the rate of creation of electric charges at cloud tops by the ionosphere-ground (air-earth) current in AEC which can be sensitive to CR variations. These results demonstrate the need for studying the response of AEC to the modulations of CR by solar wind.
    The influence of CR on AEC is realized mainly through the atmospheric conductivity which is a result of ionization. GCR of energies <10^11 eV are the only factor of ionization of the air between 5 km and 35 km, and have a contribution to the ionization up to 90 km in the daytime and up to 100 km at night, i.e. GCR are necessary for creation and maintenance of AEC. Their 11-year variations during the solar cycle lead to changes in stratospheric conductivity, so that it is larger during solar minimum than during solar maximum, respectively. The relative factor of solar cycle change of the stratospheric conductivity is about 3% at equatorial, 10% at tropics, 20% at middle, and 50% at high and polar latitudes (according to the results of Velinov & Mateev 1990). This leads to a small decrease of the average air-earth current at polar latitudes during solar maximums compared to solar minimums. At equatorial and low latitudes the variation of the air-earth current will be yet smaller. Larger atmospheric conductivity changes, involving larger range of altitudes (possibly, tropospheric) take place during a Forbush decreases of GCR and especially during a SEP events.
    https://www.swsc-journal.org/articles/swsc/full_html/2013/01/swsc120040/swsc120040.html

    • Hydrogen atoms have a high cross section when it comes to GCR’s, so something with a lot of hydrogen in it, like polyethylene, makes good shielding. You can dope it with boron to soak up the secondary particles.

      • Mike McMillan,
        You mistake GCR’s for neutron radiation. Hydrogen atoms are 1 proton nucleus (mostly). They make good neutron absorbers. Think deuterum creation.
        They suck at absorbing relativistic protons (GCRs). I’ll leave it to you to think about why.

      • Boron is just for the secondary neutrons?
        (no, I know nuffin on this. I find the protons coming at the speed of light really annoying feature of the space)

    • I think that is a mistake. I believe if the ray goes through the material there aren’t many if any secondary particles. If the ray actually does, by accident hit something, then it generates tons of secondary particles.

  6. I got out my trusty RADEX RD1503 dual-tube Geiger-Mueller detector and turned it on. Right on normal for cosmic ray flux at 0.17 MSv/hr. Actually, with the decreasing strength of our magnetic field I expect more cosmic rays to reach “ground level”, but not for now. Looks like if you are not going to the moon or Mars everything is still OK. Let’s face it : Explorers have always plunged off into the unknown with a little reckless abandon, bless them.

      • Max, you can also amuse your friends with the K radiation coming from bananas with the RADEX (or any other radiation detector). I’ve noticed though that some friends don’t think that’s funny.

      • Max,
        Can you handle the truth?
        Are you someone who avoids boiling things in plastic so you don’t get cancer?
        Are you someone who buys organic? So you don’t get Cancer.
        So many people do all this crazy stuff to not “get cancer”. Yet they eat bananas. Fly on jets in the stratosphere.
        Crazy.
        They can’t handle the truth.

      • I don’t know whether to laugh or cry when someone tells me they only “eat organic” because they would never knowingly put “toxins” in their bodies, yet they are covered with tattoos that use industrial-grade synthetic inorganic pigments used to stripe highways and paint Honda Accords, based on cadmium and other heavy metals.

      • People are funny about that magical substance called pink Himalayan sea salt. They say it’s healthier than that evil “processed” table salt, because the pink stuff has “84 trace minerals”. When I point out that that list includes plutonium, uranium, cadmium, mercury, and other goodies, they say well yes, but those are in such small doses that it doesn’t matter. (Sorry, you can’t have it both ways.)
        Now when the pink stuff is around I always say, “please pass the plutonium.”
        Here is the label from the Himalayan sea salt peddled by the gander of all quacks, Mercola:
        Hydrogen — 0.30 g/kg
        Lithium — 0.40 g/kg
        Beryllium — under 0.01 ppm
        Boron — under 0.001 ppm
        Carbon — under 0.001 ppm
        Nitrogen — 0.024 ppm
        Oxygen — 1.20 g/kg
        Fluoride — under 0.1 g/kg
        Sodium — 382.61 g/kg
        Magnesium — 0.16 g/kg
        Aluminum — 0.661 ppm
        Silicon — under 0.1 g/kg
        Phosphorus — under 0.10 ppm
        Sulfur — 12.5 g/kg
        Chloride — 590.93 g/kg
        Potassium — 3.5 g/kg
        Calcium — 4.05 g/kg
        Scandium — under 0.0001 ppm
        Titanium — under 0.001 ppm
        Vanadium 0.06 ppm
        Chromium — 0.05 ppm
        Manganese — 0.27 ppm
        Iron — 38.9 ppm
        Cobalt — 0.60 ppm
        Nickel — 0.13 ppm
        Copper — 0.56 ppm
        Zinc — 2.38 ppm
        Gallium — under 0.001 ppm
        Germanium — under 0.001 ppm
        Arsenic — under 0.01 ppm
        Selenium — 0.05 ppm
        Bromine — 2.1 ppm
        Rubidium — 0.04 ppm
        Strontium — 0.014 g/kg
        Ytterbium — under 0.001 ppm
        Zirconium — 0.001 ppm
        Niobium — under 0.001 ppm
        Molybdenum — 0.01 ppm
        Ruthenium — under 0.001 ppm
        Rhodium — under 0.001 ppm
        Palladium — under 0.001 ppm
        Silver — 0.031 ppm
        Cadmium — under 0.01 ppm
        Indium — under 0.001 ppm
        Tin — under 0.01 ppm
        Antimony — under 0.01 ppm
        Tellurium — under 0.001 ppm
        Iodine — under 0.1 g/kg
        Cerium — under 0.001 ppm
        Praseodynium — under 0.001 ppm
        Neodymium — under 0.001 ppm
        Samarium — under 0.001 ppm
        Barium — 1.96 ppm
        Europium — under 3.0 ppm
        Gadolinium — under 0.001 ppm
        Terbium — under 0.001 ppm
        Dysprosium — under 4.0 ppm
        Holmium — under 0.001 ppm
        Erbium — under 0.001 ppm
        Thulium — under 0.001 ppm
        Ytterbium — under 0.001 ppm
        Lutetium — under 0.001 ppm
        Hafnium — under 0.001 ppm
        Tantalum — 1.1 ppm
        Wolfram — under 0.001 ppm
        Rhenium — under 2.5 ppm
        Osmium — under 0.001 ppm
        Iridium — under 2.0 ppm
        Platinum — 0.47 ppm
        Gold — under 1.0 ppm
        Mercury — under 0.03 ppm
        Thallium — 0.06 ppm
        Lead — 0.10 ppm
        Bismuth — under 0.10 ppm
        Polonium — under 0.001 ppm
        Astat — under 0.001 ppm
        Francium — under 0.10 ppm
        Radium — under 0.001 ppm
        Actinium — under 0.001 ppm
        Thorium — under 0.001 ppm
        Protactinium — under 0.001 ppm
        Uranium — under 0.001 ppm
        Neptunium — under 0.001 ppm
        Plutonium — under 0.001 ppm

      • I cannot agree with you on plutonium in himalyan sea salt.
        To be sure, Plutonium in our environment does exist today.
        It got here from fission bomb tests starting 1945.
        All naturally occurring plutonium from our stellar nursery days long ago decayed away.
        Himalyan sea salt is many thousands of years old. The recently created plutonium from reactors and dispersed by bomb tests is not inside pink salt.

      • Joel, excellent point and well taken. And I really only showed the product’s label for entertainment value — that is, that a peddler of woo ends up with such an amusing list of “benefits”.
        Shoot. “Pass the plutonium” had such a nice alliteration.

      • Regarding your comment “please pass the plutonium”, you may want reconsider it as the data that you tabulated indicates that plutonium was not detected. It is common for analytes that are not detect to be reported as “less than” or “under” at the particular analyte’s analytical detection limit. In this case the detection limit for plutonium appears to be 0.001 mg/Kg that is also expressed as 0.001 parts per million (ppm ) which can be expressed as 1.0 microgram/Kg that is the same as saying 1.0 parts per billion (ppb). A quick glance at the tabulated data indicates that most of the analytes were not in fact detected, so perhaps “please pass the platinum” would be more accurate.

    • “I got out my trusty RADEX RD1503 dual-tube Geiger-Mueller detector and turned it on. ”
      And you will be able to identify specific keV’s
      Geiger counters are so passé

      • Or look at Be7 in rainwater associated with increased Cosmic rays.
        “Be-7 radioactive nuclei with a half-life of 53.3 days result from spallation reactions of galactic cosmic rays(GCR) “

      • HI Mike from Au, when I was President of a uranium exploration company I carried around a Terraplus RS-125 Gamma-Ray Spectrometer which utilized the different KeV levels to allow for K, U, and Th assays directly in the field at an outcrop. Have you ever heard the over-dose alarm on a 125 go off? However, this little RADEX is my personal fits-in-your-pocket size detector and it’s with me when I’m fishing, checking radiation levels of dinosaur bones in museums (excuse me Mr. Curator, where did you collect his bone?), searching for bananas in the supermarket, etc.

      • Max Photon (great handle by the way) , are you suggesting we should launch astronaut mission in future in specially adapted Honda Accords – better than plastic Tesla’s I don’t doubt.

    • Not sure why people think plutonium cannot occur naturally.
      Just think about how we “manufacture” it in a nuclear reactor, and it should be clear that naturally occurring U235 and U238 will produce tiny quantities of plutonium through chance reactions in the ores in which it is part of.
      It the Uranium is then dissolved and distributed (in tiny quantities) into deposits of sea-salt, one can expect tiny-tiny quantities of plutonium as well. Some isotopes of plutonium have half lives of millions of years – so if you can detect a quantities of parts-per-trillion, you likely will find traces of plutonium in anything derived from evaporating sea water.
      It isn’t enough to be worried over.

  7. The reality is that radiation protection is a requirement for anything humans do beyond Low Earth Orbit.
    A one-meter-thick water ice protective shield around habitats would provide sufficient protection.

    • At a weight of one metric tonne per square meter of shielding, unadjusted for ice expansion.

      • Keeping that ice frozen up in my attic here in Houston would cost a tonne. I’ll just leave the tinfoil shielding up there.

      • Igloos are made from blocks of compacted snow, either névé or firn. Not ice. You can easily cut firn/névé with a saw. Ice is hard. You need power tools or lots of muscle power to cut and lift it.

      • Cover the crew capsule in 1 M thick ice with thick tinfoil to stop sublimation. Ice makes good rocket fuel and provides radiation protection. Win-Win. Why aren’t we blasting out ‘ice bullets’ in cylindric cans on mag lev boosters at escape velocity from earth to LEO where we can use H2O in space for a lot of stuff. Use the empty ‘cans’ to build the next space station or permanent spaceship to Moon/Mars. C’mon Elon, use your imagination.

  8. In 2014, Schwadron and his team predicted around a 20 percent increase in radiation dose rates from one solar minimum to the next. Four years later, their newest research shows current conditions exceed their predictions by about 10 percent, showing the radiation environment is worsening even more than expected.
    No, just showing that their model was no good to begin with.
    http://www.leif.org/research/Goelzer-Paper-2014.pdf

  9. Just read it the other day on an astronomy site. Beginning to look like even trips to Mars might be, at best, a severe life-shortening adventure. At the least, the ISS is showing us these things beforehand. Going to have to come up w/some kind of light-weight but effective radiation-shielding.

  10. Can’t we just dispense with the “an history” locution? The usage “a history” is the most correct English.
    [The mods need to think about an historical pattern to that proposal … .mod]

    • Oxford Dictionary is behind you.
      “People often believe that they should use the indefinite article an in front of words like historic, horrific, or hotel. Are they right or wrong? Should you say ‘an historic event’ or ‘a historic event’?
      An is the form of the indefinite article that is used before a spoken vowel sound: it doesn’t matter how the written word in question is actually spelled. So, we say ‘an honour’, ‘an hour’, or ‘an heir’, for example, because the initial letter ‘h’ in all three words is not actually pronounced. By contrast we say ‘a hair’ or ‘a horse’ because, in these cases, the ‘h’ is pronounced.
      Let’s go back to those three words that tend to cause problems: historic, horrific, and hotel. If hotel was pronounced without its initial letter ‘h’ (i.e. as if it were spelled ‘otel’), then it would be correct to use an in front of it. The same is true of historic and horrific. If horrific was pronounced ‘orrific’ and historic was pronounced ‘istoric’ then it would be appropriate to refer to ‘an istoric occasion’ or ‘an orrific accident’. In the 18th and 19th centuries, people often did pronounce these words in this way.
      Today, though, these three words are generally pronounced with a spoken ‘h’ at the beginning and so it’s now more logical to refer to ‘a hotel’, ‘a historic event’, or ‘a horrific accident’.”

  11. Can’t we just build a spacecraft with a magnetic field to deflect charged cosmic rays? What percentage of cosmic rays have no charge?

    • The (charged) cosmic rays are so energetic that the magnetic field would have difficulty “bending” them away from the spacecraft hull. The rays that hit the hull create secondary radiation, so that needs to be considered.
      Not impossible, but tricky to make an “inverted” gamma ray deflector without having to launch the weight of the magnets too: Think of the gigantic structures and weight needed for a cyclotron (which uses a circular array magnets to “drive” charged particles into a tightly focused racetrack “circle” inside the magnets), then think of trying to intercept randomly incoming charged particles and divert them away from the center of the magnets where the hull is. Difficult.

    • All the craft needs is a molten iron core (and therefore it possesses a magnetosphere), I have been led to believe.
      Good luck with the molten iron part, unless it’s an integral part of your power supply too…

      • A negatively charged monopole would work stuck on a long pole at one end of the spacecraft. A positively charged monopole at the other end. What you don’t deflect with the + monopole, the – monopole attracts.
        Just invent a monopole and problem solved (for GCRs at least).

      • Been doing experiments with a friend and we have been creating magnetic fields a quarter mile in diameter that magnetise hollow steel objects, i.e. cars fridges washing machines e.c.t. a half HP motor driving our device makes this field. So a large magnetic barrier in the future could be the way to go.

    • The problem is the speed of the charged particles (and of course the fact there are non-charged particles, but that’s a different discussion).
      You either must supply a incredibly powerful magnetic field to deflect charged particles in a small amount of time (and therefore space), or you must provide a weak magnetic field to slowly deflect the particles over a large amount of time (and therefore space). The sun has a relatively weak magnetic field (out past the orbit of Earth) but it occupies a huge volume of space, so can effectively deflect a lot of charged particles.
      A spaceship would need to devote a large amount of energy to producing a strong magnetic field to be effective against energetic charged particles. It is likely more efficient to interrupt these particles using a barrier than to produce a strong enough magnetic field to accomplish the same degree of safety. It might be possible (and more efficient) to combine both types of protection using less of each but they are additive.
      The real problem is always mass. You need a lot of mass to create the energy you need for producing a strong magnetic field, or a lot of mass to add an effective barrier. More mass, more expensive to build and harder to move about (accelerate). This means you want a small an area as possible to protect, and so the astronauts end up cramped up in a sardine can. This leads to wanting to put the astronaut into a “sleep” state so that they do not need to move about, or no astronaut at all but just genetic material to grow new people once to get somewhere (interstellar travel).
      Eventually producing a craft capable of keeping humans semi-safe from radiation is mostly just an engineering problem, and will likely be solved through future technology breakthroughs. Traveling long distances in space and time is a limitation of physics as we understand them, and so there may never be a gratifying solution to traveling to other stars – it will remain a one-way trip for the individual and might only include our DNA as cargo.

  12. Tsk..how many times does poor Leif have to come here and tell everyone that changes in the behaviour of the SUN have ABSOLUTELY NO EFFECT on the earth or its atmosphere?
    Can’t you all just accept what he says?

    • … sarcasm, I assume, Charles N.
      It seems that life on Earth has continued because of a certain regularity with the effects of the sun, as far as the planetary surface goes. I’m not entirely convinced yet that there is “absolutely no effect”, however, but I appreciate Leif’s effort to insure that we don’t jump the gun on causation here. I’m still weighing the arguments (since 2009).

      • Well Robert I’m not so sure myself…but Leif is, poor guy’s practically hoarse from repeating it!

      • Many solar physicists think that changes in the behaviour of the Sun do affect Earth’s atmosphere, Charles. lief isn’t the only pebble on the beach. Neither was Lord Kelvin, thank goodness…..

    • I too appreciate Leif’s posts here. He has definitely, shall we say, enriched my view of Maxwell’s Equations. I am still not sure what to make of it all, but I do like seeing things from a different angle. Plus I admire that he takes heat and dishes it out like a man.

    • JH,
      Lead foil or tungsten foil might be a little more effective than the aluminum that has come to be called “tin foil.”

  13. This is merely an incident of incomplete records. What has the spaceweather been doing for the last 4 billion years? So foolish to post such a thing, when we do not know, we do not know. Stop already…

    • I’m sorry, I missed the implication that this is anything other than a notable phenomenon of an ancient cycle. It seems appropriate to our good host to discuss current solar and heliospheric events for those who follow that subject. Just because there is no such discipline as paleo-heliospherics does not mean that we should ignore the current observations and consider them as foolish.
      The “stop” part is your choice. You may ignore this thread at your discretion.

    • “We do not know” used in science is like saying “God made it”. It’s 100% NOT allowed, ever, ever, ever. We just know to different degrees of certainty and science is very, very certain on everything. Ask Mikey Mann.

  14. Since cosmic rays are a kind of radiation, they can hurt people and machines. Lucky for us, Earth’s magnetic field and atmosphere protect us from most cosmic rays. On average, people get hit with about 2.3 millisieverts of radiation each year. A millisievert is a unit for measuring radiation. It is abbreviated mSv. Cosmic rays make up about 0.2 mSv of the radiation we get each year. That isn’t very much; less than 10% of the total. Astronauts do have to worry about cosmic rays, though. If astronauts travel away from Earth (to the Moon or Mars, for example), they aren’t protected by Earth’s magnetic field any more. They could get hit by as much as 900 mSv of cosmic ray radiation in a year! Cosmic rays can damage our DNA and cause cancer and radiation sickness. Scientists will have to figure out how to protect astronauts from cosmic rays before we can send a mission to Mars.
    When cosmic rays hit Earth’s atmosphere, they crash into atoms and molecules of gas. That usually makes even more cosmic ray particles! Since there are more particles, the energy from the cosmic ray from space is spread out. The new cosmic ray particles often hit other gas molecules. That makes still more cosmic rays, but with lower energies. The collisions between cosmic rays and gases in the atmosphere can happen many times. In the end, there might be thousands or millions of “secondary” cosmic rays. This is called an “air shower” of cosmic rays.
    Earth doesn’t always get hit by the same number of cosmic rays. Strangely, cosmic rays are less of a problem when the Sun is most active. Sometimes there are more solar flares and other “space weather storms”; sometimes there are fewer. The Sun has a cycle that is 11 years long. At “solar max” the Sun is very active; at “solar min” there are very few “storms” on the Sun. Since some cosmic rays come from the Sun, you might think that there is more danger from cosmic rays when the Sun is active. Good guess; but wrong! When the Sun is active, it “puffs up” its heliosphere. Like Earth’s magnetic field, the Sun’s magnetic field helps shield us from galactic and extragalactic cosmic rays. So an active Sun means better shielding! So, if you’re an astronaut, the best time to be going on a long trip in space is when the Sun is most active.
    https://www.researchgate.net/publication/281441974_Geomagnetic_Field_and_Climate_Causal_Relations_with_Some_Atmospheric_Variables

  15. There’ll be somewhere between two and five metres of water surrounding space craft in hexagonal tubes. Water is useful anyway – hydroponics, sewage recycling, air cleaning, oxygen regeneration, heat exchanges, perhaps even steam power generation and fish farming. Apparently you can even drink the stuff.

    • Water makes life possible on Earth and in space.
      We just have to get past the “Earth to Low Earth Orbit” hurdle, and then humanity is off to the races. Look out universe, here we come!

  16. Of course the September 2017 SEP event(s) had nothing whatever to do with Hurricanes Harvey, Irma, and Maria. Or did they? Coincidence?

    • Sophocles-
      Lets not forget about the earthquake (s) that occurred within two days after the event.

      • No. I haven’t forgotten them but they are just “More Coincidences.” According to the SkepSky-ants, esp. Dana Nuttycherry-picker, the coming solar minimum is only going to cause less than 0.3°C cooling. They forget about the increasing cosmic rays, and the increasing cloudiness. What’s the bet it’s going to be more like greater than 1°C cooling? ..

  17. “with four parameters I can fit an elephant, and with five I can make him wiggle his trunk”, “And with six free parameters I can make the elephant fly.” Can’t remember who said it.

  18. Don’t worry, the magic molecule CO2 will protect us from another Maunder Minimum type of cooling for the next 50 years. Belief is half the battle. Just ask Peter Pan.

  19. Papers read like poorly written science fiction. “could” “might” “maybe” There is NO science whatsoever anymore, just a bunch of hypotheticals that would make any con man beam with pride.

  20. No worries, NASA has this all covered. But GCRs greater than we thought means cooling greater than we thought. If true, well the launder is back and the LIA cooling from if was worse than we thought and recovery from the LIA chops off a degree that we had to worry about before. So 2.5 to 3C becomes the actual problem. :Houston, we don’t have a problem!”

  21. Commentators are falling for the exaggerated effect of this ionising radiation. Did you know that for mice, the optimum dose for both longevity and growth rate is ~1000x background? (Lorentz et al 1957). I would not recommend that for humans – about 20x background or 50mGy/yr. BTW, there are millions of people who receive in excess of 50mGy/yr and up to >1000 who do not suffer from radiation overdose. Also, BTW 99+% of DNA damage is caused by metabolite oxidants (Feinendegen et al). If you want to reduce DNA damage then try convincing folks to get less exercise and see how that works!

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