Future of U.S. Mars exploration, an update on the Mars InSight mission, the debate over planning for the Lunar Orbital Platform-Gateway, the past, present and future of Mars rover missions, the use of VR for exploring Mars, NASA’s search for exo-planets, SpaceX plans for the Red Planet and a full review of the Mars Society’s Mars Desert Research Station and the most recent University Rover Challenge.
Does the thought of mutations in your DNA (and other bits of your body’s cells) scare you? Do you worry about toxins, or GMOs, or species-hopping viruses? Cancer, or growing a second head? Here’s something that may terrify you. Or, since it happens every day and you’re not dead yet, maybe comfort you.
Here’s how you mutate. Your body contains a lot of carbon. This is such a basic fact that to say a chemical is organic means it contains carbon atoms in its molecules. Your DNA, the genetic blueprint that pilots your cells through life, contains carbon atoms.
Carbon, like many elements, exists in different forms called isotopes. Mostly we have carbon-12, but a fraction of all carbon is carbon-14, which is radioactive. When it decays (that is, releases a sub-atomic particle or energy from its nucleus), it transmogrifies into a different element, nitrogen.
Isaac Asimov once estimated that this transmogrification happens roughly six times a second somewhere in the DNA in your body, every second of every day, throughout your life. I’m way too lazy to check his figures, but whatever the rate, it happens. Every one of these events mutates the DNA where it occurred. A lot of the mutations will be in body cells, and some will be in sperm or eggs (reproductive cells.) A mutation might kill the cell, cause cancer, get passed on to offspring, or do nothing discernable.
So, you are a mutant. So am I. And we’re still alive. Do you feel better? Or worse?
BTW: Carbon-14 is created in Earth’s atmosphere every day by a natural process. Cosmic radiation strikes our planet from every direction, and it includes sub-atomic particles known as neutrons. Occasionally a neutron strikes a nitrogen atom. Our atmosphere is roughly 75% nitrogen, so this is no surprise.
The neutron reshuffles nitrogen’s nucleus and transforms it to carbon-14, which is radioactive and so decays back to nitrogen. It takes 5,700 years for half of a given amount of C-14 to decay, but it happens at a steady rate. The entire process happens at a steady rate and the C-14 way up high mixes into the air down low that we breathe, so the amount of C-14 in the body of any living organism stays constant until it stops breathing (or otherwise respiring). Then radioactive decay depletes the body of C-14. This is the basis of carbon-14 dating, which you may have heard of.
BTW2: Asimov’s book is old – published in 1988 – but still worth reading. He covers a lot of history and basic science. New discoveries seldom change what we know about the basics, like radioactive decay.
Busy summer? Indulge yourself. Fit short reads into your day. Or take a handful of stories on your vacation, or your staycation. Free downloads! Find your new favorite author! Get a taste of what’s available here.
A few years ago I remarked on the strange fact that wildlife is better off living in a radiation/contamination area where there are no people, than sharing a clean habitat with us. Recent studies show that’s still true.
You may recall that, in 1986, explosions destroyed a nuclear reactor at the Chernobyl power plant in Ukraine, and released huge amounts of radioactive fallout. Residents were evacuated and a large exclusion zone created, where no one was allowed to live. Scientists have entered, and recently the area was opened to tourists. Wildlife viewing may be a good reason to travel there, because removing people created a de facto preserve.
Initial studies were depressing. The radiation killed trees, and deformed animals and birds were spotted. Animal populations dipped for a while. But recent studies find that many species have multiplied enormously. The list is impressive:
- wild boar,
- roe deer,
- red deer,
- white-tailed eagle,
- black stork,
- western marsh harrier,
- short-eared owl,
- and herds of European bison and Przewalski’s horse introduced since the accident to take advantage of this “involuntary park.”
With Chernobyl, the first thing people think about are mutations, [however] we have no evidence to support that this is happening. It is an interesting area of future research, but it is not something I would worry about.
The nuclear accident was a horror, but this aftermath holds hope. Nature can bounce back if we give her a chance.
Commemorate the Earth’s largest recorded asteroid impact today, International Asteroid Day.
In 1908, a powerful asteroid struck the Podkamennaya Tunguska River in a remote Siberian forest of Russia. The event leveled trees and destroyed forests across 770 square miles, which is equal to the size of three-quarters of the US state of Rhode Island. The impact threw people to the ground in a town 40 miles away.
In science it often happens that scientists say, ‘You know, that’s a really good argument; my position is mistaken,’ and then they would actually change their minds and you never hear that old view from them again. They really do it. It doesn’t happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. Carl Sagan
It happened again, in the prestigious New England Journal of Medicine. Stay with me – there’s statistics – but it’s worth the read.
A 2013 study of the Mediterranean diet claimed proof that people eating the fruits/vegetables/olive oil/nuts/fish diet were less likely to experience a heart attack or stroke than people eating a low-fat diet.
Statistical problems were discovered and the study retracted and revised to say, while the subjects had fewer heart attacks and strokes, the diet wasn’t proven to be the reason.
Okay, this may not seem earthshaking. But how it happened is so cool.
We can thank John Carlisle, a British anesthesiologist.
He wrote a letter to an anesthesiology journal bemoaning the fact that his field was polluted by one researcher’s data that many suspected were problematic. The journal editor told Carlisle to prove it.
He studied statistical methods so he could prove it, and got over a hundred papers in his field retracted. But Carlisle wasn’t done. He looked at many more papers in many fields and found 2% were flawed – that they claimed to use a gold standard of randomized trials but had blocks of non-randomized data. (There, that’s the statistics part.)
The lead author of the 2013 Mediterranean diet study quickly acknowledged the problems when Carlisle pointed them out and revised the paper. That’s got to hurt. Studies cost a lot of time and money, but he did it. Carl Sagan would be proud.
If that still doesn’t sound earthshaking, consider that studies like these can impact the health of millions of people all over the world. And that “paper mill” journals with fewer scruples than the NEJM have sprung up recently, further complicating our lives.
Carlisle praised the journal’s response. ‘I think that the NEJM editorial team responded very maturely to my paper,’ he says. ‘They took the possibility of a problem seriously and acted quickly and thoroughly.’
That’s science. That’s why science transforms our lives.