So what do penguins and Venus have in common?
OUR ACCIDENTAL UNIVERSE
by Chris lintott
(Torva £22, 272pp)
Afew decades ago, two groups of astronomers made the same discovery about the expansion of the Universe. By measuring the brightness of certain supernovae, they found that it was speeding up.
The trouble was that both groups had set out to measure how much it was slowing down. Under the influence of gravity, it certainly should have been.
‘The cause of this unexpected acceleration, perhaps a previously unsuspected kind of force that accounts for as much as 70 per cent of the energy in today’s Universe, remains the greatest mystery in cosmology,’ says Chris Lintott.
‘we astronomers like being surprised,’ he adds. Lintott is a professor of astrophysics at Oxford and the presenter of The Sky At
Night on BBC TV. His new book is an enjoyable tour of astronomical discoveries, aimed at the general reader.
Some of his stories are about familiar objects in the night sky. Twenty thousand asteroids that cross earth’s orbit, for example, are now known. More are discovered each week. Some are given names.
All the individual Beatles have asteroids named after them. There is an asteroid catalogued as Mr. Spock, although this honours not the Star Trek Vulcan but a cat owned by an asteroid-hunting astronomer.
In 2017, an unfamiliar object in the solar system was picked up by a telescope in
Hawaii. Initially thought to be an asteroid or a comet, it was neither. Nor was it, as some speculated, an alien spacecraft.
It proved to be the first sizeable interstellar object — something that has travelled into the solar system from outside and is therefore not gravitationally bound to the sun — to be identified.
Given the Hawaiian name Oumuamua, it was a transient visitor from the unfathomable depths of space.
As Lintott writes: ‘Oumuamua had found its way here from beyond our little corner of the Milky way, travelling for perhaps billions of years.’ It didn’t need to be piloted by aliens to be an exciting discovery.
Are there aliens out there? The question of whether we are the only beings in the Universe intelligent enough to contemplate its wonders fascinates us. Given the billions upon billions of stars and the recent evidence
of planets orbiting so many of them, this seems unlikely. Astronomers have long speculated about the existence of other beings in the solar system.
William Herschel, the 18th- century scientist who discovered Uranus, even believed the sun was likely to be inhabited. In the 19th century, observations of what appeared to be artificially created canals on Mars prompted thoughts of Martians who had built them.
It’s now vanishingly unlikely that there are ‘little green men’ anywhere nearby.
However, as Lintott points out, the possibility of some form of life elsewhere in our solar system still exists.
Enceladus, a moon of Saturn, is about the size of the British Isles. When Nasa’s Cassini probe passed near Enceladus’s surface, it unexpectedly revealed jets of water shooting into space from its south pole. And where there’s water, there might be life. Even Venus might not be as inhospitable as it seems. Analysis suggests that a gas called phosphine is present in the clouds above the planet.
On Earth, phosphine is produced in some living creatures, most notably in the stomachs of penguins. No one is suggesting that Venusian penguins float through its atmosphere but phosphine is an indication that something — bacteria perhaps — might be present there.
Over the last century, new ways of learning about the Universe have been developed. Most recently, the James Webb Space Telescope was launched into orbit. ‘Whenever we have looked longer, deeper, further or in new ways at the Universe,’ Lintott writes, ‘it has surprised us.’ His excellent book is a layman’s guide to the surprises.