Voyager 2 met Uranus on January 24, 1986


Voyager 2 met Uranus on January 24, 1986. Image by way of NASA/JPL.

Today in Science: Voyager 2 met Uranus

On January 24, 1986, the Voyager 2 spacecraft swept previous Uranus, the solar system’s distant seventh planet. The craft got here inside 50,640 miles (81,500 km) of its icy blue-green cloud tops. Thus Voyager 2 turned the primary – and thus far the one – human craft to go to this planet. During its closest strategy, and within the weeks earlier than and after, Voyager 2 transmitted a treasure trove of scientific knowledge that totally modified our view of this enigmatic, distant world.

Many exceptional discoveries got here from this cosmic meetup. Data from Voyager 2 revealed {that a} Uranian day is simply 17 hours and 14 minutes lengthy. It confirmed that Uranus’ ambiance is much like that of the opposite fuel giants, composed primarily of hydrogen and helium. Below that lay water, ammonia and methane ices.

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Pale blue-green planet against a black sky.
Voyager 2 captured this view of the largely featureless mild green-blue disk of Uranus on January 14, 1986, when it was about 7.8 million miles (12.6 million km) from the planet. Image by way of NASA.

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Uranus, the tilted planet

Scientists knew, from telescopic observations made out of Earth earlier than Voyager 2 met Uranus, that the planet’s rotation axis was tilted at 98 levels. In different phrases, the planet’s polar axis lies virtually within the airplane of its orbit. Scientists suppose a collision with a planet-sized object early within the solar system’s historical past tipped Uranus on its aspect. As a outcome, Uranus has, maybe, the most interesting seasonal patterns within the solar system.

Voyager 2 revealed that Uranus has a weird magnetic discipline. The planet’s magnetic discipline tilts 59 levels from Uranus’ axis of rotation. This creates a non-uniform magnetic discipline for Uranus that may vary in strength by up to 10 times.

Voyager 2 discovered that Uranus has radiation belts comparable in depth to these of Saturn. Earth additionally has radiation belts, with the 2 foremost ones generally known as the Van Allen belts.

Diagram: Axis of planet plus curved lines coming out from planet on both sides.
A diagram of Uranus’ magnetic discipline primarily based on knowledge from Voyager 2. It’s tilted 59 levels from the axis of rotation. The magnetic south and north poles have the labels S and N. Image by way of Ruslik0/ Wikimedia Commons.

The many moons of Uranus

Voyager 2 met not solely Uranus however its many moons. Initially, scientisits found 10 new moons within the knowledge Voyager 2 despatched again, for a total of 15 moons recognized on the time. In 1999, extra evaluation of Voyager 2 knowledge revealed an eleventh moon. Today, we all know of 27 moons orbiting Uranus.

Among the newly found moons was Puck, simply 100 miles (160 km) in diameter, with a grey, closely cratered floor.

Voyager 2 additionally imaged the Uranian moons we already knew, revealing their superb geology.

The final Uranian moon found earlier than Voyager 2’s arrival was Miranda. Gerard Kuiper discovered it in 1948. Thanks to Voyager 2, we noticed Miranda rather more clearly. In reality, it earned the nickname of Frankenstein moon due to its unusual patchwork look.

A small, irregular, textured rock against a black background.
Voyager 2 found Puck, one of many moons of Uranus. The spacecraft took this picture on January 24, 1986, at a distance of about 306,300 miles (500,000 km). Image by way of NASA.
Round gray moon with craters, lines, streaks and white patches.
Miranda’s sharp and numerous options earned it the nickname Frankenstein moon. Image by way of NASA/ JPL.

Rings and issues

By the time Voyager 2 met Uranus, scientists had already found Uranus’ rings from Earth. Voyager 2 surveyed Uranus’ rings and found two new ones, bringing the total variety of rings to 11. Today, there are 13 recognized rings.

Section of many concentric rings of Uranus with short white streaks in foreground.
A backlit view of the Uranian ring system reveals high-quality particles distributed by means of the rings. This picture was taken simply 147,000 miles (240,000 km) away from the planet. Image by way of NASA/ JPL.

And so Voyager 2 vastly elevated our data of Uranus, after which left this world behind for one ultimate rendezvous, with Neptune in August 1989, earlier than heading out of the solar system. In December 2018, NASA introduced that Voyager 2 had entered interstellar space. Now, forty-four years after it launched from Cape Canaveral in 1977, the spacecraft is sort of 12 billion miles (19.3 billion km) from residence.

By the best way, it was the well-known astronomer William Herschel who discovered Uranus. It was the primary planet found with a telescope and the primary added to the group of bright planets – Mercury, Venus, Mars, Jupiter, Saturn – recognized since antiquity.

Uranus is the third-largest planet in our solar system. It may comprise 63 Earths. But it isn’t a vibrant planet as a result of it’s very distant, about 1.9 billion miles (3 billion km) from the sun, or 20 instances the Earth-sun distance.

Bottom line: Voyager 2’s closest encounter with Uranus occurred on January 24, 1986. It’s the one spacecraft to have ever visited this frigid world within the outer solar system. It left a wealthy legacy of knowledge that has endlessly modified our view of that pale green-blue planet.

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