Tag Archives: Voyager 2

Voyagers’ 40 Year Eternal Mission

On the 20th of August 1977 it started – Voyager 2 was launched. Then on the 5th of September the twin spacecraft Voyager 1 was launched. Despite being the second to be launched Voyager 1 was names number one as it would arrive at it’s destinations before it’s sister craft.

Voyager Timeline


On the 5th March 1979 and the 7th of July 1979 respectively they arrived at their first destination. For the first time we could see Jupiter and it’s moons in high quality. Even though they only flew past they found Volcanoes on Io, Jupiter’s rings, Europa’s ice cracked surface and more moons to add to it’s already large number.








After this they both went on to Saturn, Arriving on the 12th of November 1980 and August the 25th 1981 respectively.


saturn voy 2

saturn voy 1

They found a frozen world, which much like Jupiter had storms, we saw the rings of this world in more detail than ever before and it’s largest moon, Titan was found to have a thick atmosphere.wp-1504725033753.

At this point Voyager 1 was flung from the solar system by Saturn’s gravity, Voyager 2 continued the mission to the last of the outer planets alone.



So far every planet had it’s surprises, and Uranus was no exception. On the 24th of January Voyager 2 made it’s lonely flyby and a planet that was almost completely featureless. Magnetic instruments found it was like the planet had been knocked on it’s side, both the rings and the planets magnetic field were side on to the other planets.



Miranda, one of it’s moons had a crazy mashed up surface, broken up by gravitational pulling. Voyager 2 added more moons to the planets number.



On the 25th August 1989 Voyager 2’s final visit in our solar system had finally been reached.


Neptune was again a very different world, made mostly of Methane this beautiful blue world showed off the great black spot – a storm that looked like an eye looking out at you. With Winds faster than the speed of sound this was not all Neptune revealed.

Neptune’s largest moon Triton was found to have active ice volcanoes, introducing us to the concept of cryo volcanism. Voyager found some faint rings and more moons for the blue giant.


After Neptune, there wasn’t much or the Voyager probes to do, February 1999 Voyager 1 took a last look back at the solar system and the planet from where it came and took a last picture – a portrait of the solar system.

Voyage Portrait

In 1999, Voyager 1 passed Pioneer 10, becoming the furthest man made object in space.

In 2004 and 2007 respectively the spacecraft encountered the terminator shock as they left the solar system and entered interstellar space. They are now on their way to the stars. Carrying with them records and messages from humanity from who or whatever might encounter them.

Despite being launch 40 years ago their mission may never end, ambassadors to eternity to the species that made and launched them hoping to make their mark in the universe. If left alone these two incredible machines will outlive not only the race that made them, but also the planet from where they came.

Now that it truly incredible.

Simon 🙂

No ownership claimed on images Credit to NASA and JPL.


Solar System Exploration – Neptune


Neptune was discovered in 1846, the credit of discovery is split between Urbain Le Verrier and John Couch Adams. Both these astronomers used permutations in the orbit of Uranus to locate Neptune before observing it.  Neptune is the only planet to have been discovered from mathematical computation rather than direct observation. Although Galileo had observed Neptune in 1613 and had mistaken it for a star, so he is not credited for it’s discovery. Neptune is named after the Roman God of the sea and is also known as Poseidon as the Greek god of the sea.

Neptune is composed of an icy / metallic core and a helium / hydrogen atmosphere, the core making up  90% – 95% of it’s mass. The remaining 5% = 10% is it’s helium / hydrogen atmosphere. By comparison the core’s  is  between 10 x and 15 x Earth’s mass.


Facts about Neptune

Some of the key facts about Uranus and how it compares with Earth:

  • Diameter 49,200km (3.8 x Earth’s)
  • 1 Neptune Day = 16h 06m hours long.
  • 1 Neptune year = 165 years.
  • Atmosphere = 18% Hydrogen, 19% Helium.
  • Volume = 57 times that of Earth.
  • Distance from the Sun = 30 x further than Earth.
  • Neptune has 14 known moons.
  • Mass is over 17 x  Earths mass, but spread over a larger object.



Moons and rings

Many of Neptune’s moons have not been discovered until recent times, some not until the 1980’s from Earth and then in 1989 with the Voyager 2 flyby and still subsequently with Hubble.

Neptune has some amazing names attached to it’s Moons like Triton, Larissa, Thalassa, Despina and Galatea. Here a few that we know something about.



Triton is named for the son of Poseidon in Greek mythology, it was discovered in 1846 by William Lassell.

Triton has a retrograde orbit, this means it orbit Neptune the opposite way to the other moons, because of this and it’s similar composition to Pluto it’s been suggested that Triton is a captured dwarf planet.

Made up of a surface of frozen nitrogen and 30-40% water ice. Triton is a very cold place to be with temperatures of -38K (-235C). Despite these frozen conditions Triton is one of the few moons in the solar system that’s know to be volcanic.

The volcanism doesn’t involve hot lava as on Earth, rather this is cryo volcanism. The sub surface Nitrogen vapourises under the surface until the pressure build enough to erupt to the surface. When Voyager 2 passed by in 1989 it captured images of geyser like eruptions coming from the surface.













Names after the shape changing God of the sea Proteus is 420km across and is the second largest of Neptune’s moons. It was discovered by Voyager 2 while on approach to Neptune. It wasn’t discovered from Earth because it is so close to Neptune.




Larissa was discovered from Earth by a star occultation in 1981. It’s the fourth largest of Neptune’s moons and is made up of debris from other moons smashed up by Triton.



During the Voyager 2 flyby’s it discovered and photographed the rings of Neptune, faint and thin but several sets of rings were discovered. This settled a long standing discussion about discoveries of ring from Earth that couldn’t be substantiated. As usual these rings are likely to be made up of rock and ice.




This is the final piece in Holst’s The Planets suite. With Neptune being 30x further from the sun than the Earth it’s a mysterious place and this is beautifully captured in his piece in Neptune.



Recent Events

The first and only spacecraft to have visited Neptune is Voyager 2 back in 1989. It carried out a flyby mission, taking photographs taking measurements of Neptune and it’s moons, finding out anything it could about this mysterious world.


What was immediately obvious is that Neptune is a world that’s very different from it’s neighbour Uranus. Neptune is a world that is visibly active with storms that have wind speeds over the speed of sound, clouds and spots.

Voyager 2 picked up the great dark spot on it’s approach, with smaller storms in in the lower bands of the planet. As Neptune is so far from the Sun, the most likely cause of these storms is the internal heating effect of the planet itself. Voyager found so much when it visited this distant and mysterious world, things that from Earth would be so difficult to observe. Storms, rings, volcanoes on Triton. There was far more than anyone expected or could have hoped for.

Artist’s impression of how Triton, Neptune’s largest moon, might look from high above its surface. The distant Sun appears at the upper-left and the blue crescent of Neptune right of centre. Using the CRIRES instrument on ESO’s Very Large Telescope, a team of astronomers has been able to see that the summer is in full swing in Triton’s southern hemisphere.

There are no plans to go back and visit Neptune in the near future. The legacy that Voyager left behind as it left our solar system lives on though. With so much to go back for it’s only a matter of time before blue gem has to give up it’s secrets for us.

Simon 🙂

No ownership claimed on images – Credit NASA / ESA.