Posts Tagged ‘Christiaan Huygens’

In my first post about the Voyager space craft, I mentioned that I was going to be talking about the Voyager space probes on live TV on Thursday the 27th of September. This has now been shifted to next Thursday, the 4th of October, giving me time to write part 2 of this blog on their incredible journey. In this part I will talk bout the visit of Voyager 1 to Titan, Saturn’s largest moon, and Voyager 2’s visit to Uranus and Neptune. In part 3, which I will post early next week, I will talk about their ongoing journey beyond our Solar System.

Voyager 1’s encounter with Titan

When Pioneer 11 flew by Saturn in 1979 it detected that Titan, Saturn’s largest moon, had a thick, gaseous atmosphere. Titan was discovered by the Dutch astronomer Christiaan Hyugens in 1655, and had long held fascination for planetary scientists. That Titan may have an atmosphere was first suggested by Josep Comas Solà in 1903. This was confirmed by Gerard Kuiper in 1944.

It was decided by NASA’s Jet Propulsion Laboratory to alter the course of Voyager 1 to go and study Titan in more detail by flying close to it. This effectively meant that it would not be able to continue on to visit Uranus and Neptune, as had originally been planned.

Voyager 1 image of Saturn’s largest moon Titan, which was discovered by the Dutch astronomer Christiaan Huygens in 1655

The pictures Voyager 1 took of Titan have proved vital to our understanding of this planet sized moon. This next picture shows the haze that Voyager 1 was able to see in Titan’s atmosphere. The close fly-by of Voyager 1 also showed that Titan’s thick atmosphere is impenetrable at visible wavelengths, so Voyager 1’s cameras were not able to see any surface detail. Voyager 1 was able to determine that the atmospheric pressure at the surface of Titan was about 1.5 times the atmospheric pressure at the surface of the Earth.

Voyager 1 observed a thick layer of haze above Titan’s atmosphere

Voyager’s encounter with Uranus

With Voyager 1’s close fly-by of Titan taking it out of the plane of the Solar System, it was left to Voyager 2 to continue the grand tour on to Uranus and Neptune. Voyager 2 flew by Uranus in January 1986. For both Uranus and Neptune, the images taken by Voyager 2 are still the most detailed we have of these “ice giants”. Voyager 2 discovered several new moons orbiting Uranus, and was able to study its planet’s atmosphere in more detail than before.

Voyager 2’s image of Uranus

A crescent Uranus, taken as Voyager 2 looked back towards Uranus as it heads off towards Neptune.

Voyager 2 also studied the rings of Uranus. These were first discovered in 1977 by the Kuiper Airborne Observatory, during an occultation.

Uranus’ ring system, as imaged by Voyager 2

Voyager’s encounter with Neptune

Voyager 2 finally arrived at Neptune in August 1989. Very little was known about this planet prior to Voyager 2’s visit.

Voyager 2 image of Neptune

Voyager 2 also took an image of Neptune and its largest moon Triton as it continued on its journey to the outer reaches of the Solar System.

Voyager 2 looks back at Neptune and its largest moon Triton as it continues on its journey to the outer reaches of the Solar System

Part 1 of this post is here, and part 3 is here.

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