BET À DAY
We pretty much know how it all started, some 13.8 billion years ago. The big bang transformed the universe into a cosmic ball of fire, creating stars, galaxies and planets and driving its continued expansion. A rocky planet that was called Earth, “a speck of dust lost in a universe as vast as it is diverse”, was thus formed and developed into what we know today.
But how will it all end? Because our universe does indeed have a programmed end. In some five billion years, our sun will swell and swallow up everything around it. The Earth will be nothing more than a vulgar charred pebble devoid of life. It's not me who says it, but a recognized scientist, Katie Mack, a cosmologist and astrophysicist who studies the Universe in its entirety.
In principle, she says, it should be possible to survive the death of a planet.
“Billions of years from now, it is conceivable that humanity will continue to exist, in perhaps unrecognizable form, venturing into the far reaches of space, finding new homes and building new civilizations. »
Knowing this, what meaning can we give to our life? Obsessed by the very real possibility that in the blink of an eye, the cosmic apocalypse will occur and that our universe could cease to exist, Katie Mack wants to bring her grain of salt here, outside of any religious consideration. The frail humans that we are, she says, are incapable of influencing or bringing about the end of the cosmos, but they can at least understand it. A kind of “intellectual luxury”. She thus offers us five possible scenarios with as many different apocalypses: the Big Crunch, “which will occur if the current course of cosmic expansion is reversed”; the endless expansion of dark energy; or its heartbreak; the appearance of a “deadly quantum bubble that devours the cosmos”; and finally the collision with a parallel universe.
Collision announced
These scenarios are all currently under the magnifying glass – increasingly powerful telescopes – of scientists. Moreover, the author invites us to observe in the sky, on a moonless autumn night, the great W drawn by the constellation Cassiopeia. “If you stare for a few seconds into space below, if the sky is dark enough, you will see a faint diffuse spot, roughly the size of the full moon. This is the Andromeda galaxy, a huge spiral disk made up of a trillion stars and a supermassive black hole; this set is charging towards us at the speed of 110 kilometers per second. Four billion years from now, Andromeda and our Milky Way will collide, creating a pretty light show.” Something to send shivers down your spine.
Some astronomers refer to the existence of a vast cosmic energy field “capable of forcing the vacuum of space itself to undergo an intrinsic outward thrust […] which would cause the Universe to expand forever”. Another possible death, faster this time, may come from dark energy – “something that accelerates the expansion of the Universe” – “the aptly named 'Big Rip' or Big Rip >. […] This alarming possibility is not a far-fetched idea, assures us the scientist. In fact, the best cosmological data available to us not only do not exclude it, but they even seem to timidly point in this direction. Our universe would experience a kind of unraveling, an evaporation before entering total darkness. No possible survival. Quite a dismal ending.
New Big Bang?
It could be a depressing book, with no hope of survival. Everything we have built over the centuries will disappear. No inheritance possible. Any trace of our civilization or that which will exist in five billion years will be destroyed, burned, pulverized. It's far, I know, and above all we can't help it. But in the meantime, more than the thermal death of our universe or its disintegration by vacuum, it is our planet Earth that we must worry about.
Slim hope. The author goes so far as to affirm that even after the thermal death of our universe, “nothing prevents a fluctuation from causing a big bang to arise from nothing to make the Universe start again”.
< strong>READ ALSO
Car-Free Neighborhoods/From Audacity to Reality
The author, Stéphane Boyer, is mayor of the second largest city in Quebec, Laval, in the northern suburbs of Montreal. He proposes in this audacious book nothing less than to create car-free zones! We all know more or less what buying a car means for the environment: construction of roads, infrastructure and highways, pollution with more GHGs, urban sprawl, etc. However, by making neighborhoods denser, we can “reduce car travel, because the distances to be covered are shorter and dense neighborhoods are better suited to being served by public transport. A dense neighborhood also makes it possible to have shops such as pharmacies, daycare centers or even grocery stores within walking distance”. We could thus “recover the space occupied by roads and infrastructure dedicated to the car at the local level”. But this clashes with the desire of many of those fleeing Montreal to have more space to live with their families. Reconciling these needs and desires requires that we can at least talk about them, and this is what the mayor of Laval is proposing.
What life owes to death /When the family matriarch bows out
Well-known storyteller Boucar Diouf, the most Quebecois of Senegalese, lost his 87-year-old mother in 2021, “the central pillar of the family, the one who prefers the word that unites to the words that divide”. Nothing will be like before. There are those people whose disappearance leaves a void that is difficult to fill, says Boucar, and his mother is one of them. His dreaded disappearance was announced to him in the middle of the night by a phone call. It's as if we had suddenly pulled on a piece of thread, thus completely undoing, one stitch at a time, “that good old knit that was so comfortable that kept us warm and that we thought was eternal”. And it is by sharing his sorrow and his pain with us that he will manage to calmly find a smile, he says. Paradoxically, this book is a touching ode to life, as only Boucar knows how to do, where the analogy with the habits and customs of elephants never ceases to surprise us. “In some African traditions, the elephant symbolizes cooperation, intelligence and devotion,” he concludes. We still have a lot to learn from these pachyderms.