Its like a game of cat and mouse. Every time astronomers think they are getting close to understanding the universe, mother nature throws them another curveball to contend with.
Today’s googly comes from the H0LiCOW collaboration and takes the form of a faster than expected expansion rate for the universe. Based on new observations taken with the Hubble Space Telescope, it confirms that a serious discrepancy lies at the heart of our astronomical understanding.
The rate at which the universe is expanding is a fundamental quantity with which to test cosmological theory. It is called the Hubble Constant after Edwin Hubble, the American astronomer who first measured it in 1929.
Ways to measure Hubble’s constant fall into two camps: the study of relatively nearby celestial objects, and the study of far distant radiation left over from the origin of the universe.
Both methods should give the same expansion rate. The trouble – as confirmed today – is that they don’t.
The problem was first seen last June, when another team of astronomers known as the SH0ES project, published a surprisingly high Hubble Constant that conflicted with the value from two spacecraft: NASA’s WMAP and ESA’s Planck.
WMAP and Planck had calculated relatively slow Hubble Constants from the Universe’s microwave background radiation, which was produced during the split second in which the universe came into existence.
At the time, the astronomers were so confident with the spacecraft that they began referring to the era of ‘precision cosmology’. In their opinion, just about everything was known about the make-up of the universe, with just the astronomical ‘i’ dotting and ’t’ crossing to be done.
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Today’s results, which are to be published in a series of five papers by the UK’s Royal Astronomical Society, show that there is much more to be done than the fine detail.
In a statement accompanying the results, H0LiCOW team leader Sherry Suyu, Technical University Munich Germany said, “The expansion rate of the Universe is now starting to be measured in different ways with such high precision that actual discrepancies may possibly point towards new physics beyond our current knowledge of the Universe.”
The bottom line is that the universe to almost certainly more complex than we thought – and its already byzantine. To explain other puzzling observations, cosmologists have postulated a number of substances that affect the expansion rate.
Firstly there is dark energy, which is designed to accelerate the expansion of the universe. Maybe these new observations suggest that it is growing in strength.
Secondly, there is dark matter. Despite suspecting its existence for decades now, astronomers and physicists are no closer to detecting a single particle of the stuff. Could it be behaving in a way that affects the expansion?
Thirdly, could there be a kind of dark radiation? This would invisibly carry energy around the cosmos, altering the expansion.
Fourthly, could there be a problem with Einstein’s general theory of relativity? This is the mathematical framework that astronomers use to calculate Hubble’s Constant based on the matter and energy contained in space. If those equations are even slightly off, then we could have everything else right and still be getting the wrong answer.
As yet no one knows which is the more likely solution.
Today’s results confirm that what started as a niggle has grown into a full-blown problem for cosmology. Put simply, our picture of the Universe does not add up and that means there is probably something fundamental we have not yet understood.
This is a good thing. The potential for discovery is huge. Exciting times are ahead.
It’s 40 years since Richard Dawkins suggested, in the opening words of The Selfish Gene, that, were an alien to visit Earth, the question it would pose to judge our intellectual maturity was: “Have they discovered evolution yet?” We had, of course, by the grace of Charles Darwin and a century of evolutionary biologists who had been trying to figure out how natural selection actually worked. In 1976, The Selfish Gene became the first real blockbuster popular science book, a poetic mark in the sand to the public and scientists alike: this idea had to enter our thinking, our research and our culture.
The idea was this: genes strive for immortality, and individuals, families, and species are merely vehicles in that quest. The behaviour of all living things is in service of their genes hence, metaphorically, they are selfish. Before this, it had been proposed that natural selection was honing the behaviour of living things to promote the continuance through time of the individual creature, or family, or group or species. But in fact, Dawkins said, it was the gene itself that was trying to survive, and it just so happened that the best way for it to survive was in concert with other genes in the impermanent husk of an individual.
This gene-centric view of evolution also began to explain one of the oddities of life on Earth – the behaviour of social insects. What is the point of a drone bee, doomed to remain childless and in the service of a totalitarian queen? Suddenly it made sense that, with the gene itself steering evolution, the fact that the drone shared its DNA with the queen meant that its servitude guarantees not the individual’s survival, but the endurance of the genes they share. Or as the Anglo-Indian biologist JBS Haldane put it: “Would I lay down my life to save my brother? No, but I would to save two brothers or eight cousins.”
The original book cover, illustrated by Desmond Morris.
These ideas were espoused by only a handful of scientists in the middle decades of the 20th century – notably Bob Trivers, Bill Hamilton, John Maynard Smith and George Williams. In The Selfish Gene, Dawkins did not merely recapitulate them; he made an impassioned argument for the reality of natural selection. Previous attempts to explain the mechanics of evolution had been academic and rooted in maths. Dawkins walked us through it in prose. Many great popular science books followed – Stephen Hawking’s A Brief History of Time, Stephen Pinker’s The Blank Slate, and, currently, The Vital Question by Nick Lane.
For many of us, The Selfish Gene was our first proper taste of evolution. I don’t remember it being a controversial subject in my youth. In fact, I don’t remember it being taught at all. Evolution, Darwin and natural selection were largely absent from my secondary education in the late 1980s. The national curriculum, introduced in the UK in 1988, included some evolution, but before 1988 its presence in schools was far from universal. As an aside, in my opinion the subject is taught bafflingly minimally and late in the curriculum even today; evolution by natural selection is crucial to every aspect of the living world. In the words of the Russian scientist Theodosius Dobzhansky: “Nothing in biology makes sense except in the light of evolution.”
Back in the 1980s, it fell to the BBC to switch on the light for me. Repeats of David Attenborough’s 1979 series Life on Earth were the prime source of my exposure to natural selection, and though wondrous, the scientific content is slight. But if Attenborough was the gateway drug to a love of evolution, Dawkins made me an addict. My father, a psychologist, had a first edition of The Selfish Gene, the hardback with the Monty Python-esque cover, those strangely evolved shapes stalking a surreal landscape drawn by the zoologist Desmond Morris. Dawkins’s prose is lucid and powerful, his argument difficult to contend. I bought my own copy at university, and when I pulled it from my shelf today, tucked inside I found my old University College London photocopier credit card, a Proustian trigger to my undergraduate days in the 1990s.
It is a shame that Dawkins is now perhaps better known for his irritable contempt for religion, since his true legacy is The Selfish Gene and its profound effect on multiple generations of scientists and lay readers. In a sense, The Selfish Gene and Dawkins himself are bridges, both intellectually and chronologically, between the titans of mid-century biology – Ronald Fisher, Trivers, Hamilton, Maynard Smith and Williams – and our era of the genome, in which the interrogation of DNA dominates the study of evolution.
Since 1976, our understanding of why life is the way it is has blossomed and changed. Once the gene became the dominant idea in biology in the 1990s there followed a technological goldrush – the Human Genome Project – to find them all. Then it turned out that we didn’t have enough genes to account for our presumed sophistication, and that the genome itself was replete with DNA that wasn’t made up of genes. Many of these areas were genetic control switches, the on and off buttons to tell genes where and when to function. Some are just the decaying remains of genes whose function have been lost in time.
Genes aren’t what they used to be either. In 1976 they were simply stretches of DNA that encoded proteins. We now know about genes made of DNA’s cousin, RNA; we’ve discovered genes that hop from genome to genome, inserting themselves into a new host to be replicated there. And what by far the larger part of the genome is doing for much of the time is still something of a mystery. Today we can scan genomes by the hundreds and look for the signals of natural selection in DNA, regardless of what that DNA is actually doing. It’s like knowing an animal had been there by finding its prints in the forest. Genomics has become an industry devoted to trying to work out the immense complexities of DNA. None of the complications of modern genomes erodes the central premise of the selfish gene.
Dawkins himself has attracted more than his fair share of animosity over the years. Setting aside the response to his views on religion and politics, there have been plenty of attacks on the idea of the selfish gene. When I was an undergraduate, I recall a tutor rather shirtily suggesting that I should read some papers rather than “that book”, and The Selfish Genehas been attacked variously by philosophers, comedians, vicars and journalists too. Much of the enmity stems from people misunderstanding that selfishness is being used as a metaphor. The irony of these attacks is that the selfish gene metaphor actually explains altruism. We help others who are not directly related to us because we share similar versions of genes with them.
In the scientific community, the chief objection maintains that natural selection can operate at the level of a group of animals, not solely on genes or even individuals. These exchanges, such as with the great entomologist EO Wilson, are often ill-tempered spats, in which entrenched positions are expressed with animosity. To my mind, and that of the majority of evolutionary biologists, the gene-centric view of evolution always emerges intact.
It’s also an idea that permeates all biology, right back to the beginnings of life on Earth. We’ve made great strides in understanding the process by which chemistry on Earth became biology. Life was simpler then, and the first information encoded in a gene would probably have simply been the instruction to replicate itself. Molecules that do just that have been created in the lab, or, more precisely, have been allowed to create themselves by a process of chemical natural selection. We will never know whether these self-replicators are like the ones at the beginning of life, because those are lost to very ancient history. But the premise remains exciting that a gene’s only desire is to reproduce itself, and that the complexity of genomes makes that reproduction more efficient.
Richard Dawkins today: he has regretted the title of his book, since many failed to see ‘selfish’ was being used metaphorically. Photograph: Murdo Macleod for the Observer
Where Dawkins places the origin of life squarely with the origin of replicators, ie the first gene, an emerging view suggests otherwise. This view (as I argue in my most recent book) is that this process – genetics – followed the establishment of a system that could host that information replication. Genes in cells rely on a metabolism that generates the power needed for them to enact their programmes and replicate themselves. It seems to me to be important that we try to understand the origins of biology by modelling what living things actually do. Logically, a metabolism of sorts must have preceded the establishment of the first selfish gene, and some of us now think that it might have occurred deep in the geological crannies in the ocean floors some 4bn years ago.
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Life has been continuous on this planet ever since – on a sort of single evolutionary tree (which more like sprawling tangled thicket now). We share dozens of genes with our most distant relatives, single-celled bacteria and archaea. These are probably the most successful – the most selfish – of any genes, since their existence spans the entire duration of life on Earth.
Richard Dawkinshas occasionally lamented his own choice of the “selfish gene” title since it has for decades been misinterpreted by detractors and fools. He has said he might have preferredThe Immortal Gene. I disagree, as immortality implies foresight, and is for ever. Species go extinct, and genes can be lost even after millennia of success. Life has no plan other than to keep chugging along. Nevertheless,The Selfish Genehas attained its own literary and scientific immortality: as long as we study life, it will be read.
Will the Earths Magnetic Fields Shift, NOVA Wikipedia: "Mario Acuña (March 12, 1940 – March 5, 2009), born in Córdoba, Argentina, was a research scientist at NASA Goddard Space Flight Center in the Space Plasmas and Planetary Magnetospheres Branches, and then as a Senior Astrophysicist. He was a major pioneer in the field of planetary magnetism.
Acuña became a naturalized U.S. citizen in April 1994. He earned a B.A. degree from the Universidad Nacional de Córdoba in 1962, an MSEE degree from the Universidad Nacional de Tucumán in 1967, and a Ph.D. in Space Physics from the Catholic University of America in 1974.
Acuña was a principal investigator on magnetometer experiments flown on numerous missions over the years, from the Pioneer 11 Fluxgate Magnetometer Experiment in 1973 to the Mars Global Surveyor Magnetic Field Experiment in 1994, and the MESSENGER magnetometer. He was also the recipient of many professional awards, including election to the National Academy of Science, the Moe Schneebaum Memorial Award (the highest engineering award at Goddard), the NASA Exceptional Scientific Achievement Medal, and the NASA Distinguished Service Medal.
Dr. Acuña died March 5, 2009, aged 68, of multiple myeloma (cancer) at his home in Bowie, Maryland.
