Sci-fied reality is very much here and now. The
twenty-first century arrived almost twenty years ago, and it is no
surprise that flying taxis, choppers in space, bot-human love stories or
even the existence of a new species existence get written every other
day. Alongside all of this, there are scientists like Adam Rutherford,
who says that the ultimate storage device will be made of DNA.
This,
of course, raises the important question: What are humans really, when
it comes to consideration of genetics? Much as we think of ourselves as
sophisticated species, we have fewer genes than a grain of rice. Yet, we
are the only ones to ask, “What are we?” This enigma lies at the heart
of Rutherford’s new book, A Brief History of Everyone Who Ever Lived.
A riff on Stephen Hawking’s most accessible
work, this book is heavy on ambition while being quick in pace and
sweeping the reader off their feet from the word go. Rutherford, a
geneticist who hosts the popular BBC Radio 4 show, Inside Science, sets
the bar high by explaining how homo sapiens ought to understand the basic building block of life, the gene, to understand who we really are:
“Our
genomes, genes and DNA house a record of the journey that life on Earth
has taken – 4 billion years of error and trial that resulted in you.
Your genome is the totality of your DNA, 3 billion letters of it, and
due to the way it comes together – by the mysterious (from a biological
point of view) business of sex – it is unique to you. Not only is this
genetic fingerprint yours alone, it’s unlike any of the other 107
billion people who have ever lived.”
Perhaps to drive
home this point, Rutherford serves up a crash course on the side in
understanding gene studies, involving genome sequencing, DNA, genomes,
alleles, chromosomes and more. To understand the gene, time travel is a
must. After all, out of the six homo species, only ours has survived, having emerged some 30,000 years ago. The others were on earth for about 2 million years.
Rutherford
explains that the simple chain of “monkey-ape to ape-man, to man-ape”
is an untruth. The first in a series of untruths that he illuminates in
the book. His other bone of contention is “the culturally ubiquitous
idea that genes are fate, and a certain type of any one gene will
determine exactly what an individual is like.”
All those myths
As
the writer shuffles the deck of the cards we have been dealt, the
realisation that ours might not be the first technological and cultural
species gains currency. Cave paintings have in fact been attributed to
Neanderthals by some. And, lest we contest our brutish selves, there is a
theory that we perhaps hunted and made a meal of Neanderthals as well.
But the beautiful irony of nature is such that some of us do carry
Neanderthal genes.
Rutherford’s explanation of how 107 billion
human beings came to inhabit different corners of the world goes up
against the concept of race. He writes: “The latest analyses incorporate
the fact that the current residents of a geographical area are not
necessarily very good representatives of the residents of the deep past.
Today’s Siberians are more like East Asians, but the ancient Siberians
were more like Native Americans, mixed in with some northern Eurasian.”
Identifying races, then, is pretty much like creating patterns in a
star-studded sky.
Another wrong turn in our understanding of
things, argues Rutherford, might be based on personal genome analysis,
which has become a cheap and easily accessible service. The writer is at
pains to point out that possession of certain genes cannot and do not
guarantee you will contract a particular disease. It can only speak of
your likelihood of falling prey to it, with the odds being calculated by
comparing your score with the average.
The 3 billion letters of our DNA are ready to be read, but how they need to be read is an important question, warns Rutherford.
Where do we go from here?
The
next question Rutherford tackles is: “Are we still evolving?” We aren’t
inching towards the X-Men, he reasons, but we are certainly mutating.
Vaishyas in South India are cited as proof, as seen in the abnormal reaction to many members of this “caste” to anaesthesia, ranging from no result to even death. Rutherford explains:
“By
looking into their genomes, we learnt of a single change – a random
switching of a single letter of the gene encoding the enzyme
butyrylcholinesterase (BCHE), which normally helps degrade molecules in
the blood similar to the anaesthetic.”
The startling fact that is
this realignment of the allele – the form, dominant or recessive, in
which a gene exists in an individual – in the Vaishya bloodline began at
least 1,900 years ago. For better or worse, it appears, we are a
species on the move.
On the lighter side, Rutherford offers scoops
on the Human Genome Project (which mapped each and every gene in the
human genome from both a physical and a functional perspective). For
instance, scientists placed bets in a bar on the number of genes human
beings would turn out to have as determined by the project. Rutherford’s
quirky humour is often tucked away in the footnotes, throwing up
delightful nuggets of information, such as the whimsical scientific
names of certain species – “gorilla gorilla” is a scientific name, as is
“extra extra” for a certain mollusc)
The appeal of this
essentially scientific book lies in its ability to both inspire and
provoke thought, thanks to Rutherford’s unique, rather poetic view of
genetics. When a writer says, “You carry an epic poem in your cells,”
the reader has no choice but to pay attention. A Brief History of Everyone Who Ever Lived: The Stories In Our Genes, Adam Rutherford, W&N.
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Our
complex universe—chock full of galaxies, black holes and quasars—didn't
just appear after the Big Bang. For tens of millions of years, the
universe was a ...
This handout image received via University College London shows
Galaxy MACS1149-JD1 located 13.28 billion light-years away imaged as
seen with the NASA/ESA Hubble Space Telescope
|
HO/ALMA (ESO/NAOJ/NRAO)/AFP
It
is springtime in the Northern hemisphere. Countless buds that have been
waiting patiently on the stems and branches of trees and shrubs are now
blossoming into life. The cosmic equivalent of this season is the time
between a few hundred million and a billion years after the Big Bang.
This is when the first stars and galaxies ignited, spewing light into
the dark universe.
It is a time in the history of the universe
that we are desperate to chart, because it represents part of the
cosmological story that we have yet to understand. Now astronomers have
detected oxygen in a galaxy further away than ever before – and it
existed just 500m years after the Big Bang. The results, published in Nature, are hugely important as they provide new insights into when the first stars formed.
The
period of this “cosmic dawn” is important not only because this is when
the first galaxies were born, but a crucial cosmic transition also took
place. In this process, atoms in the electrically neutral intergalactic
medium – a wide sea of hydrogen gas surrounding galaxies – were
bombarded with ultraviolet radiation escaping from the first galaxies.
This stripped away electrons from atoms and made the gas charged, or
“ionised”.
The event, called the Epoch of Reionisation, is still mysterious. We’d like to know – or better yet, see – when this process started. Part of that quest involves finding the most distant galaxies. Artist’s impression of the Epoch of Reionisation. Photo credit: ESA C. CarreauWhen
we look out into the universe we detect light that has taken some
appreciable time to traverse the gulf that separates us from other stars
and galaxies. The light from the screen you are reading this on has
taken about a third of a nanosecond to reach your eyes. Light from the
nearest star beyond our sun takes four years to reach us. Amazingly,
light from the galaxy at the centre of the new study, called
MACS1149-JD1, has taken 13 billion years to be detected here on
Earth. That means we see MACS1149-JD1 as it was 13 billion years in the
past, around 500m years after the Big Bang.
Powerful gaze
Using a telescope called the Atacama Large Millimetre/sub-millimetre Array,
the scientists detected a strong signal (an emission line) within the
distant galaxy. Just as a prism disperses the light of the sun into a
rainbow spectrum, we can disperse the light of distant galaxies, too.
This is called spectroscopy. Emission lines are bright spikes in the
spectra of galaxies that originate from different elements that can each
release light of a very specific energy.
This particular emission
line came from ionised oxygen gas. Its presence tells us that the
galaxy was forming stars at the time, because the energy required to
ionise it must have come from massive, hot, young stars. The ALMA Observatory.Carlos Padilla – Photo credit: AUI/NRAOIf
we measured the same type of gas here on Earth, we would detect it at a
wavelength of 0.088 millimetres. But other galaxies are receding away
from us due to cosmic expansion, and this causes the light they emit to
increase in wavelength during the time it takes for the photons to reach
us. The more distant a galaxy is, the larger the increase in
wavelength.
This is called redshift,
and it ultimately tells us the ratio between the size of the universe
when the light was first emitted and the size of the universe today. The
oxygen emission line observed in MACS1149-JD1 is actually detected at
0.88 millimetres – its wavelength has been stretched by a factor of 10.
This means that at the time the light was emitted, the universe was a
factor of 10 times smaller than it is today, and just four per cent of
its present age.
In this way, the ability to detect emission lines
in distant galaxies allows us to pinpoint at what stage in cosmic
history we are seeing them. But of course, the most distant galaxies are
also the faintest – you need ever more powerful telescopes if you want
to peer back further.
ALMA (consisting of 66 individual telescopes
working together) is an incredibly powerful telescope – it is
revolutionising our view of the early universe. Not only is it providing
exquisite sensitivity, but operates in part of the electromagnetic
spectrum that gives access to a wide range of emission lines. Gravitational lensing. Photo credit: NASA, ESA & L. CalcadaTo help matters, the team also exploited a natural telescope: a massive cluster of galaxies.
Light from MACS1149-JD1 has had to pass through this intervening
cluster on its journey to ALMA. This is so massive that it significantly
warps spacetime, meaning that the light is “bent” in a process called gravitational lensing. Gravitational lensing amplifies the brightness of MACS1149-JD1, making it a little easier to see.
Indirect glimpse of first stars
MACS1149-JD1 is not the most distant galaxy on record,
but what this new study adds to our understanding is an insight into
the history of the formation of the galaxy. This happened hundreds of
millions of years before the current observation, and much further back
than even the most distant galaxy known.
In fact, the presence of
oxygen in the galaxy tells us that star formation must have been going
on for some time in MACS1149-JD1. That’s because oxygen can only be
formed within stars in a process called stellar nucleosynthesis. But
what we don’t know is when those stars first ignited.
By combining data from the Hubble Space Telescope, the European Southern Observatory’s Very Large Telescope and the Spitzer Space Telescope,
the authors made a model of the “stellar population” within
MACS1149-JD1. This allowed them to estimate the mixture of stars that
give rise to the emission from the galaxy observed in certain bands of
the electromagnetic spectrum.
The
model involves estimating the “star formation history” of the galaxy,
describing the rate of production of stars in the past. The modelling
suggests that, in order to produce the observed emission, stars must
have started forming just 250m years after the Big Bang, when the
universe was just two per cent of its present age. In other words,
MACS1149-JD1 was already a fairly well established galaxy, even at this
early time.
This is a huge scientific accomplishment as it is
currently impossible to observe galaxies that existed 250m years after
the Big Bang. However, the new James Webb Space Telescope, which is due for launch in 2020, may be able to do so.
But
until then, thanks to the new study, we now have a way of indirectly
studying when stars first formed in ancient galaxies like MACS1149-JD1.
In effect, by observing the blossom, astronomers have estimated when the
bud first opened. James Geach, Royal Society University Research Fellow, University of Hertfordshire. This article first appeared on The Conversation.
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Anita
Sengupta, an Indian-American from West Bengal is the mastermind who
worked on NASA's physics experiment to create the coldest spot in the
universe.
After
a year of waiting, NASA's Cold Atom Laboratory will go to the
International Space Station and the main brain behind this project is
the Indian-American ...
India
News: MUMBAI: The main brain behind Nasa's latest physics experiment to
create the coldest spot in the universe — Anita Sengupta, an
Indian-American ...
Since
ancient times, the absolute zero temperature concept has always been a
source of fuel for the scientific community. This is the temperature
near which all ...
