You just can’t miss it. Venus. With sunrises coming so late, the planet shines high in the southeastern sky around 7 a.m. and competes well against the bright blue twilight. It’s the current standout planet in the morning sky as Jupiter is in the evening. It sure caught my attention this morning when I let out our dog Sammy for a walk.
With sunrise in the Duluth region around 7:50 a.m., I could still see Venus with ease as late as 7:30. Check it out on your way to work or while you’re waiting for the school bus. You might even find enough time between breakfast and responsibility to pull out the telescope and see the planet’s crescent moon shape for yourself. Twilight and daylight are the best times to observe Venus telescopically, because the bright sky tames its glaring brilliance, making its phase sharper and easy to see.
Farther from home, NASA announced this week that the Voyager 1 spacecraft, launched to study Jupiter and Saturn back in September 1977, has reached the edge of the sun’s sphere of influence and is now on its way to interstellar space.
Voyager 1 has crossed into an area where the velocity of the hot ionized gas, or plasma, emanating outward from the sun has slowed to zero. Scientists suspect the solar wind has been turned sideways by the pressure from the interstellar wind in the region between stars. Voyager 1 is currently 10.8 billion miles from the sun or more than three times farther than Pluto.
Our sun gives off a stream of charged particles that form a bubble known as the heliosphere around our solar system. The solar wind travels at supersonic speed until it crosses a shockwave called the termination shock. From there it moves into a transition zone called the heliosheath, where the wind slows down dramatically, but is still “hot” compared to the cold, thin gas in the space between the stars. Scientists estimate that Voyager will cross the heliopause, the final boundary between the sun’s domain and that of the distant stars, in another four years. Think for a moment about the vast influence of the star we know best – the sun’s wind fills a sphere at least 22 billion miles in diameter and counting. What new will we discover when Voyager 1 finally gets its first taste of interstellar space?
We’ve certainly tasted what winter has to offer in Duluth this month, and although it pales to the more than 400 below temperatures at Voyager’s current distance, it’s enough to catch your breath. The view of Lake Superior and the city covered in fog, created when warm air in contact the lake rises into colder air and condenses, was brrrr-eautiful!