On August 25th, 1989 the 8th planet of our Solar System was visited for the first and only time so far by any spacecraft from Earth. At this time, Alan Stern, now Principle Investigator of the New Horizons mission, was a graduate student at the University of Colorado, Boulder.
Voyager 2, passed by Neptune, on its way to Interstellar Space.
Nearly five days before its closest encounter it captured this image (left). At this point Voyager was 4.4 million miles away from Neptune. It was the final time Voyager's narrow angle camera was able to take a photo of the whole planet on approach before the planet became too large to fit in the frame.
Photos of Neptune showing the height of clouds above the rest of the 'normal' atmosphere, revealed them to be about 30 miles higher and more in some places. The typical width of each raised cloud in this photo (right) is around 24 miles across with the exception of the wide stretch of cloud at around 124 miles wide.
Neptune is six times further out from the Sun than Jupiter. That's just over thirty times as far from the Sun as we are.
There is a great deal we do not know about this planet. It is about seventeen times more massive than Earth yet nearly sixty Earths could fit into Neptune. There may or may not be a solid central core.
Neptune is the first outer planet not to be visible with the naked eye. A telescope or binoculars are necessary.
It has thirteen known moons, the largest of which is Triton which is just a little smaller than our own Moon. Voyager 2 discovered active geysers on Triton. A moon this far out, and still found to be active was not expected. In fact very little of what was discovered as Voyager 2 flew past Neptune and Triton was expected.
Even in the world of Astronomy, the old rivalry between Britain and France continues to this day over who discovered Neptune first.
After Herschel discovered the planet Uranus, or, as he himself named it, George's planet after King George (which I personally favour over Uranus ha!) there were seen to be anomalies in the planet's orbit. John Couch Adams (British) and Urbain Le Verrier (French) both began to do the maths and each calculated that there must be another planet even further out than Uranus.
Both predicted positions for this eighth possible planet but it was the Frenchman Le Verrier who finally managed to persuade Germans Heinrich Louis d'Arrest (student of Galle) and Johann Gottfried Galle at the Berlin Observatory to take a series of observations where he predicted it should be. Galle found it to within one degree of where Le Verrier predicted it. The year was 1846.
A verbal and written battle over who knew it was there first and who discovered it first was eventually declared a draw, and the International Astronomical Union gave credit to both Le Verrier and Adams. However both countries still declare being the first!
Twenty five years later to the day, New Horizons spacecraft cross the orbit of Neptune on its way to Pluto. It was a long way from Neptune but took a snapshot of the lonely blue planet that only Voyager 2 has ever visited. When will we go back I wonder.
NASA's Pluto-bound New Horizons spacecraft captured
this view of the giant planet Neptune and its large moon Triton on July
10, 2014, from a distance of about 2.45 billion miles (3.96 billion
kilometres) - more than 26 times the distance between the Earth and sun.
References used in this article
Images of Neptune credits NASA.
http://www.britannica.com/biography/Heinrich-Louis-dArrest
www.nasa.gov
http://sci.esa.int/solar-system/35654-neptune/
There is a great deal we do not know about this planet. It is about seventeen times more massive than Earth yet nearly sixty Earths could fit into Neptune. There may or may not be a solid central core.
Neptune is the first outer planet not to be visible with the naked eye. A telescope or binoculars are necessary.
It has thirteen known moons, the largest of which is Triton which is just a little smaller than our own Moon. Voyager 2 discovered active geysers on Triton. A moon this far out, and still found to be active was not expected. In fact very little of what was discovered as Voyager 2 flew past Neptune and Triton was expected.
Even in the world of Astronomy, the old rivalry between Britain and France continues to this day over who discovered Neptune first.
After Herschel discovered the planet Uranus, or, as he himself named it, George's planet after King George (which I personally favour over Uranus ha!) there were seen to be anomalies in the planet's orbit. John Couch Adams (British) and Urbain Le Verrier (French) both began to do the maths and each calculated that there must be another planet even further out than Uranus.
Both predicted positions for this eighth possible planet but it was the Frenchman Le Verrier who finally managed to persuade Germans Heinrich Louis d'Arrest (student of Galle) and Johann Gottfried Galle at the Berlin Observatory to take a series of observations where he predicted it should be. Galle found it to within one degree of where Le Verrier predicted it. The year was 1846.
A verbal and written battle over who knew it was there first and who discovered it first was eventually declared a draw, and the International Astronomical Union gave credit to both Le Verrier and Adams. However both countries still declare being the first!
Twenty five years later to the day, New Horizons spacecraft cross the orbit of Neptune on its way to Pluto. It was a long way from Neptune but took a snapshot of the lonely blue planet that only Voyager 2 has ever visited. When will we go back I wonder.
NASA's Pluto-bound New Horizons spacecraft captured
this view of the giant planet Neptune and its large moon Triton on July
10, 2014, from a distance of about 2.45 billion miles (3.96 billion
kilometres) - more than 26 times the distance between the Earth and sun.
Credits: NASA/Johns Hopkins University Applied Physics Laboratory
References used in this article
Images of Neptune credits NASA.
http://www.britannica.com/biography/Heinrich-Louis-dArrest
www.nasa.gov
http://sci.esa.int/solar-system/35654-neptune/
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