Venus (left), photographed in 1974 by the Mariner 10 spacecraft, and Jupiter (right) as seen by the Hubble Space Telescope in 2020. To observe the planets planetary conjunction from anywhere across Canada this week simply look west about an hour after sunset.NASA
Like partners in a celestial dance, a pair of planets that have been lighting up the evening sky this month are set to swap positions then go their separate ways.
Venus and Jupiter are the two brightest objects that can be seen from Earth, not including the sun and the moon. Whenever they get together – an event known as a planetary conjunction – the result is an eye-catching combination.
Such pairings are not especially rare. The collective motion of Earth, Venus and Jupiter around the solar system causes Venus to appear to overtake and pass Jupiter in the sky about once every 13 months.
But this winter has provided a particularly good version of the heavenly manoeuvre that can be followed each night like a slow-motion ballet.
To observe the spectacle from anywhere across Canada this week simply look west about an hour after sunset. Venus is the brighter of the two planets and at the beginning of the week it will be lower in the sky, but the gap between them is rapidly closing.
The Globe and Mail
When the planets are at their closest together on the evening of March 1 they will appear side by side with Venus on the right. From our point of view, the narrow gap that separates them will seem no larger than the diameter of the full moon.
But this apparent convergence of distant worlds is an illusion – like a gag photo in which a person in the foreground appears to be holding a large object, such as a statue or building, in the palm of their hand.
In reality, Jupiter is nearly 850 million kilometres away from us, while Venus is about one quarter that distance. But the positions of the planets relative to Earth this week have put them together on the same line of sight.
From March 2 onward Venus will appear increasingly higher on successive nights, growing in prominence through March and April, while Jupiter sinks down and disappears into the twilight glow.
Jupiter (upper left) and Venus as seen in Toronto on February 18 after sunset. Both planets are easily bright enough to be captured with a cell phone held up to the sky as was done here. A well-mounted digital camera can provide even better results.Ivan Semeniuk/The Globe and Mail
Together the planets make for an interesting contrast. Venus is a terrestrial world, primarily made of rock but clothed in a dense atmosphere with bright clouds of sulphuric acid that enhance its brilliance.
In comparison Jupiter is a mammoth world, a giant ball of liquid hydrogen and helium that has no solid surface and a roiling atmosphere topped by frozen crystals of ammonia.
What the two have in common is that both are inhospitable to life.
In our solar system, only Earth, with an atmosphere that includes oxygen and clouds made of water vapour, offers an environment in which life can flourish.
For scientists searching for clues to life on other worlds the message is clear: All planets can be alluring when seen from afar. But in most cases their beauty is sterile.
As studies of planets around other stars commence with the James Webb Space Telescope and other high-powered instruments, we may soon come to learn just how exceptional our home in the universe truly is.