Scientific discovery is a funny thing. Sometimes it occurs quite accidentally, sometimes after a conscious search.
A perfect example of the latter is the discovery of the planet Neptune.
Astronomers stumbled upon Neptune only after the planet Uranus — which William Herschel had found 65 years earlier — was determined to exhibit some weird orbital behavior.
Specifically, Uranus wasn’t keeping precisely to the path that astronomers had computed.
A young English astronomer named John Couch Adams calculated that this odd behavior could be explained if there was another planet beyond tugging gravitationally on it.
He even figured out where this new planet might be found; unfortunately, no one in England ever bothered to look for it.
Meanwhile, across the English Channel, the Frenchman Urbain Le Verrier was making his own calculations.
Again, no one seemed to care, but Le Verrier didn’t let that stop him. He took them to German astronomer Johann Gottfried, who aimed his telescope skyward and found the new planet — on his very first night of searching!
That was in 1846, and ever since, few beginning stargazers have even looked for this distant world, let alone found it.
It’s a challenge, no doubt about it, but now’s as good a time as any to search because this week Neptune reaches its opposition point when it not only lies at its nearest to Earth — about 2.69 billion miles — but also shines at its brightest.
Finding Neptune among the faint stars of Aquarius isn’t easy, however, and since this distant world is invisible to the unaided eye, you’ll need to use “star-hopping” techniques, as well as have a dark rural sky, binoculars and lots of patience, to spot it.
If you’re up for the challenge, the best way to locate it right now is to find Saturn, the brightest starlike object low in the southeastern sky just after dark.
With binoculars, “walk” about 2½ fields of view to the lower left of Saturn and see if you can find the star pattern shown in the illustration above.
Click here for a more detailed finder chart for the planet from The Sky Live.
I know, the stars there are very faint, but that’s where Neptune happens to lie right now. To quote engineer Scotty on Star Trek: “Aah caahhn’t chehnge the laws of physics!”
With binoculars you might spot Neptune as a faint bluish “star,” but a small telescope aimed in this direction will show a tiny bluish-green disk that distinguishes it from neighboring stars.
If you’re not sure you’ve found it, sketch the area, being careful to mark every star in its exact position. Then, a week or two later, check this same celestial region and see which of these faint objects has changed its position. That’s Neptune!
Once you find it, keep this fact in mind: ever since Pluto was reclassified as a dwarf planet in 2006, Neptune has been known as the farthest planet from the sun.
And, as challenging as Neptune might be to locate, there’s something really special about seeing with our own eyes the most distant planet of our solar system!
