If you are not familiar with CRISPR/Cas9, a quick search on this blog site using the term “CRISPR” will yield a number of pertinent articles. I have chosen one to highlight here to get you started. For those who worry that CRISPR/Cas9 is something alien to our DNA, it is not. The acronym stands for Clusters of Regularly Interspaced Short Palindromic Repeats and is embedded in DNA. CRISPR is the area of DNA that stores information when the genome is fractured by something invasive like a virus or an environmental insult (radiation). It becomes a reference library of things that negatively impact the genome.
Cas9 is a protein that specifically works with RNA to recognize DNA sequences. The protein can be used like scissors to cut out a DNA sequence that it recognizes as abnormal. When this happens naturally, DNA attempts a repair but often can make mistakes that leave imperfect strands which then become inactive. But scientists have turned CRISPR/Cas9 into a repair tool to assist DNA in editing out unhealthy strands of our genetic code and inserting healthy replacements to precise locations rather than allowing the natural attempt at repair to proceed.
Why add a CRISPR/Cas9 tool to health kits carried by future space travellers? Because galactic cosmic rays and solar radiation are part of the space environment passing through any human or other life exposed to space. These forms of radiation can have an acute effect on living things just like exposure to nuclear radiation causes changes here on Earth. Current astronauts visiting the ISS are monitored daily by NASA’s Space Radiation Analysis Group. Exposure is measured in different units. One of these is Sieverts (Sv), a measure of the health effect of low levels of ionizing radiation. Guidelines for specific organ exposures have been created as follows:
| Exposure Interval | Blood forming organs | Eyes | Skin |
| 30 Days | 0.25 Sv | 1.00 Sv | 1.50 Sv |
| Annual | 0.50 Sv | 2.00 Sv | 3.00 Sv |
| Career | 1.00 to 4.00 Sv | 4.00 Sv | 6.00 Sv |
A lethal dose of radiation as defined by the U.S. Nuclear Regulatory Commission is 4 to 5 Sieverts over a 30-day period that can lead to death in up to 50% of the exposed population within 30 days.
When the atomic bomb was dropped on Hiroshima, anyone directly below the air-detonated weapon was exposed to 155 Sv of radiation. Anyone within 500 metres of the bomb’s epicentre received 42 Sv of radiation. For the former, that’s equivalent to 1.55 million chest X-rays done simultaneously, and for the latter, 420,000.
Although space forms of radiation are less catastrophic than a nuclear weapon, they can be more insidious. That’s why the National Oceanic and Atmospheric Administration (NOAA) of the United States produces space radiation weather forecasts that monitor the Sun’s activity and cosmic radiation coming from outside the Solar System. Astronauts on the ISS plan extravehicular activities outside the station’s minimally protective walls based on these NOAA forecasts.
It should also be noted that the ISS is not in Deep Space. It is in low-Earth orbit and largely protected from space radiation sources because of the Van Allen Radiation Belt, a magnetic shield that extends well beyond the Earth’s atmosphere into near-Earth space. Astronauts that go to the Moon are not protected by the Van Allen Belt. That’s true of astronauts going to Mars as well.
With current state-of-the-art chemical rocket propulsion systems, going to Mars will be an epic voyage, each way taking six months. And the stay on Mars will be for18 months to allow for a favourable realignment to make the return trip as short as possible, another six months. The 30 months in total means an astronaut will be exposed to an estimated 1.2 Sv of radiation which exceeds the lower safety limit for blood-forming organs in our bodies. And that’s without taking into consideration solar flares and geomagnetic storms which potentially could increase radiation exposure.
So that’s why a molecular laboratory onboard Deep Space missions in the future may include a DNA repair kit such as the one these four high school students invented. A molecular lab to reverse the damage long-duration spaceflights would cause would be a welcome addition. Initial tests of the Genes in Space experiment on the ISS have shown it is not too complicated to do. Along with effective radiation shielding, a DNA repair kit may become part of the inventory future astronauts will rely on to keep healthy.
]]>“Is there anything that the National Forest Service or Bureau of Land Management can do to change the course of the Moon’s orbit or the Earth’s orbit around the Sun?”
As crazy as this question is, so is the so-called expert from the Forest Service’s response:
“I would have to follow up with you on that, Mr. Gohmert.”
Really, there’s a follow-up to this imbecilic question posed by a “learned” member of the U.S. Congress?
Here are some basic facts about altering our planet’s position in the Solar System.
A move of three million kilometres further away from our current orbit around the Sun could in theory lower global average atmospheric temperatures by 3 Celsius (5.4 Fahrenheit). How so? For the same reason that Mars being further from the Sun gets less solar radiation than Earth, an increase in Earth’s orbital distance would diminish the amount of solar radiation striking the planet’s surface and cause our atmosphere to cool.
Our current global average temperature has risen in the last century by close to 1 Celsius (1.8 Fahrenheit). The current global average today is 15 Celsius (59 Fahrenheit). And based on current climatologists’ projections, by 2060, we should reach an average of 16 Celsius (61.8 Fahrenheit).
In the Congressman’s mind maybe. By moving Earth back a few million kilometres, something we could conceivably do once a century or so, we could keep burning fossil fuels indefinitely, and keeping the cows farting away or until they come home.
But there is nothing simple about moving the Earth. The amount of energy needed to move Earth’s mass to a new orbit just a fraction of the distance proposed would be equal to thousands of times the amount of energy we humans produce today. We wouldn’t be able to do it with all the nuclear bombs in our global arsenal. Nor would we be able to do it using the thrust of thousands upon thousands of rockets equivalent in size to the Saturn V or Space Launch System. The likelihood of ever achieving that level of energy production within the next several centuries and beyond is inconceivable.
Conceivably we could use orbital mechanics to push Earth further away from the Sun. But this couldn’t be done with one asteroid or another celestial object that we could conceivably manipulate. But first, we would have to capture such an object and redirect it towards Earth. And woe to us if we should misfire and the object strikes the Earth to cause an extinction event. And even if we could do it with a few asteroids it wouldn’t be enough. In fact, the entire mass of the Asteroid Belt is equal to 5% of the Moon’s mass, and if were to redirect all of the Belt the most we would move the Earth would be three-quarters of a million kilometres further from the Sun, one-quarter of our objective.
The Sun is not constant. It changes. Our celestial best friend and neighbour is slowly getting larger as it ages. There are some who deny climate change is caused by human activity. They point to physical changes in the Sun like sunspot minimums and maximums as contributors to atmospheric warming. But sunspots have nothing to do with the Sun growing over time. Based on our current understanding of solar dynamics, in the next 100 million years the Sun’s expansion will lead to an increase of 1% in solar radiation striking our planet.
At the current rate of greenhouse gases being added to the atmosphere from human activities, we will produce the same retained solar energy effect as a swelling Sun and do it in a few centuries.
I’m talking about space mirrors or a space sunshade, an idea that has been bandied about within the engineering community going back a few decades. In 2016, the BBC published an article that described a proposal by James Early back in 1989 to build a 2,000 kilometre-wide space umbrella for diverting the Sun’s energy from striking the planet’s surface. Early thought we could source all the material needed from the Moon which would be much easier to get into orbit than if launched from Earth’s deep gravity well. The structure would be built in segments and assembled in space where it would be positioned far enough from the Earth to emulate a solar eclipse. The BBC article doesn’t mention the cost. And nor does it talk about the potential for the structure to fail and what that would suddenly do to an Earth now dependent on this enormous sunshade. Imagine how quickly the cooling would be reversed by a return to peak solar radiation striking the planet’s surface.
Another geoengineering idea that the Congressman didn’t suggest is one that Harvard University, Bill Gates and a few others have proposed. A pilot project to increase particulate matter emissions in the stratosphere to do artificially what large volcanic eruptions have done in the past has been proposed by Harvard. The proponents of this cite a recent example: Mount Pinatubo in the Philippines. The volcano erupted in 2001 and emitted an ash and gas cloud that reached as high as 50 kilometres (31 miles) in the stratosphere. Upper atmospheric winds soon disbursed the particles and gases (sulphuric acid droplets) planet-wide forming a haze that contributed to a drop in global average temperatures of 0.6 Celsius (1 Fahrenheit). The impact lasted almost two years. To create a Mount Pinatubo effect would require humans to release aerosols into the stratosphere continuously. This would involve the building of a dedicated fleet of aircraft and no one has studied how it might alter other atmospheric conditions such as impacting wind and precipitation patterns.
]]>What this means is more solar energy is reaching the Arctic Ocean surface where it gets absorbed rather than reflected back into space if ice were there. The study looks at freeze-up data from 1979 to the present using NASA’s Nimbus-7 Scanning Multichannel Microwave Radiometer, and sensors on the Defense Meteorological Satellite Program spacecraft. It shows that the biggest change is a later start to the refreezing of sea ice, as much as 6-11 days in 30 plus years. The melt onset which appears to be less affected even though that’s when solar radiation in the Arctic would be most intense because of the Sun’s higher position in the sky.
But the latter fits with other observations made on our planet. For example, here in Toronto, the warmest months of the summer don’t occur when the Sun is most directly overhead on June 21. July and August tend to be warmer than June. And Lake Ontario on which Toronto sits is at its warmest in September, three months after the summer solstice.
The Arctic ice melt research appears in the February 28, 2014 issue of Geophysical Research Letters.
Now add changes to cloud cover and the amount of solar radiation striking the Earth’s surface. How is the water cycle impacted by the combination of the two? The new study, conducted by Axel Kleidon and Maik Renner of the Max Planck Institute for Biogeochemistry, located in Jena, Germany, tested a energy balance model to determine if a warming atmosphere without or with increased solar radiation creates different results. Lo and behold they found that the water cycle is both sensitive to atmospheric temperature as well as increased sunlight. In the case of warming without sunlight factored in evaporation grows by 2% per 1 Celsius (1.8 Fahrenheit) degree. In the case of increased sunlight evaporation grows by 3% per Celsius degree.
The analogy the scientists use is one of boiling a pot of water on the stove. You can do this with the lid on or off. Increase the heat with the lid off and you can boil the water. But put a lid on the pot and reduce the heat and the water still boils.
Now consider the Earth. Turn up the heat by increasing the temperature and evaporation increases. Add more sunlight and you enhance the energy flow with or without increasing the temperature. That means even greater evaporation.
One of the ideas for geo-engineering our atmosphere in light of increased CO2 has involved reflecting sunlight away from the Earth’s surface using a number of means. These have included putting mirrors up in space to deflect sunlight, or seeding the upper atmosphere to increase cloud cover. What the study suggests is changing the amount of sunlight reaching the surface by artificial means could have unintended consequences. After all one of the hypotheses to explain recurrent Ice Ages here on Earth correlates them to changes in Earth’s orbit, axial inclination and, therefore, the amount of sunlight reaching the planet’s surface.
