Announcing a new product: another large glossy poster, like our Map of the Starry Sky and Zodiac Wavy Charts.
(Click that image to see more. It’s also now an item on the Universal Workshop website.)
This poster displays in three-dimensional space the paths of the five spacecraft that have journeyed out past the orbits of all the planets into the space among the stars: Pioneers 10 and 11, Voyagers 1 and 2, and New Horizons.
The main picture is in two parts: “close up,” showing Earth’s orbit and the craft peeling off from it in their several directions; and a vaster view as they travel into the universe.
Their trajectories, whirling around Earth so as to achieve their curves toward their destinations, make a complex pattern. To help disentangle them, color coding is used across the various features of the poster – thus, orange and red for the two Voyagers.
Besides the space views, there is a chronology of the launch dates and encounters with the planets; and explanation of the “Grand Curve” and “slingshot” effects that enabled this “Grand Tour”; and a map of the paths across the constellations as the craft fly away from us.
For example, Voyager 1’s curl around Saturn in 1980 sent it into a northward path, which has now brought it to the northern end of the constellation Ophiuchus. It looks as if it is aiming for the star called Rasalhague or Alpha Ophiuchi. This is one of the stars that are relatively bright because relatively near. Rasalhague is “only” 48 light-years away. Voyager 1 is traveling at a speed of about 3.56 AU (astronomical units, Sun-Earth distances) a year. And there are 63,240 AU in a light-year (as the poster’s useful caption explains). So to reach Rasalhague’s distance will take around 850,000 years.
Rings around Fomalhaut
Another, and nearer, of these bright-because-fairly-near stars is Fomalhaut (“mouth of the fish” in Arabic), Alpha star of the constellation Austrinusa, the “southern fish.”
Fomalhaut is 25 light-years away, about half as far as Rasalhague. To show where both these stars are in space, here is part of one of the pictures in the Astronomical Companion.
The symbols for the stars are vastly larger than the stars, which would be microscopic on this scale. A northward or southward stalk connects each star to the equatorial plane (the plane of Earth’s equator). The grid lines on that plane are 25 light-years apart. Our Sun is at the center, where two of the grid lines cross. A circle indicates the previous (smaller) sphere in the series of pictures, with radius of 16 light-years. You can see that Fomalhaut is not far outside that sphere, and south of the plane; Rasalhague is farther outside, and north of the plane.
A discovery has been made about Fomalhaut. High-resolution images taken by an infrared instrument on the James Webb Space Telescope have revealed around the star an asteroid belt, several ring-like clouds of dust, and an outer zone like the Kuiper Belt of our solar system. The gaps between these rings may be due to the gravitational effect of unseen planets.
Fomalhaut is the 18th brightest star in our night sky. It is about twice as wide and massive as the Sun. Its southerly position (declination about -24°) means that it is not easy to see from our northern hemisphere; its right ascension is about 23h, so it is highest above the southern horizon in the early night of November or the midnight sky of October.
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