Something Terrible Is Happening To Neptune

[00:00:01]Scientists were shocked [music] to find out that strange and unexpected things are happening on Neptune.

[00:00:06]Neptune is the keeper of the deep, the last known major [music] planet from the sun, the god of the boundless sea beyond the inner solar system that marks the shore of the black [music] depths of interstellar space.

[00:00:20]Neptune wasn't discovered until 1846, [music] despite having a diameter four times that of Earth and being 4.5 [music] billion kilometers away from us, making it appear small and dim even to powerful [music] telescopes.

[00:00:35]Throughout the past two decades, scientists have seen dramatic changes in the planet's atmosphere, and its [music] most recent changes have scientists worried.

[00:00:45]What's happening on Neptune, [music] and how can this have a detrimental effect on our everyday lives?

[00:00:50]Let's find out.

[00:00:55]Neptune isn't [music] something you hear much about, is it? Certainly not as frequently as the other planets.

[00:01:01]Images of [music] Jupiter's clouds and Mars's surface are frequently provided by space robots.

[00:01:08]Mercury [music] is frequently blamed for astrology enthusiasts' terrible days, even though Mercury being in [music] retrograde is actually just an optical illusion in our night sky. The Cassini spacecraft [music] orbited Saturn for 13 whole years before crashing into the planet, ending its illustrious run of observations. [music] Additionally, planetary scientists have said that NASA ought [music] to give top priority to sending a probe to Uranus in the upcoming 10 years. In fact, Neptune's [music] brief presence in the headlines due to a new study regarding what makes Neptune so blue [music] was unusual. Even that discovery, according to Patrick Irwin, the study's lead author and a planetary physicist at Oxford University, was unintentional.

[00:01:55][music] Irwin claimed that his team's goal was to research the atmospheres of Neptune and Uranus >> [music] >> rather than to look into the specific enigma of Neptune's beautiful appearance.

[00:02:08]This is how the two [music] ice giants, so named because researchers think the planets were initially glommed [music] together from icy materials, are frequently investigated. They are roughly the same size, [music] bigger than Earth but smaller than Jupiter and Saturn, and share a lot of other characteristics.

[00:02:26]They are planets without [music] surfaces that have atmospheres made of hydrogen, helium, and a small amount of methane.

[00:02:34]Scientists [music] believe that under extreme pressure deep inside these objects, diamonds are formed when carbon atoms are compressed.

[00:02:42]>> [music] >> Scientists previously knew that the methane in Neptune's and Uranus's atmospheres, which absorbs the red colors of incoming sunlight and leaves blues and greens for our eyes to view, gives them their generally bluish appearance.

[00:02:58]Erwin and his associates discovered that a certain layer of methane haze on Uranus is twice as thick as it is on Neptune though.

[00:03:07]If there were no haze, Erwin claimed, these atmospheres would be naturally blue. They get paler when haze is added.

[00:03:15]>> [music] >> The scientists hypothesized that Neptune's atmosphere, which is more turbulent, is better suited [music] to stirring up methane particles and thinning out this layer.

[00:03:25]Because of this, Neptune is the bluest planet in our solar [music] system, while Uranus is a gentle aquamarine, making them the ideal [music] contrast for our most underappreciated planet.

[00:03:38]Neptune should, in theory, be able to enjoy its position in the cosmic lineup as the planet that is furthest from the sun, but everyone is still debating whether Pluto counts as a full-fledged planet or not.

[00:03:51]Despite losing its position in the final position in 2006, when planetary scientists aren't arguing over [music] that, they're looking for planet nine, an imaginary planet that is said to orbit the sun beyond Neptune, and whose existence could be able to explain the odd orbits of some distant celestial planets.

[00:04:14]If NASA follows the advice of the scientific community and sends a spacecraft [music] to Uranus in the coming years, Neptune will be the only planet that humans have yet to visit on a special mission.

[00:04:25]>> [music] >> It wasn't until astronomers noted that Uranus, which had been discovered by telescope in 1781, >> [music] >> was being pulled about in its orbit by the gravity of an unknown celestial body, that they recognized it was there.

[00:04:40]Finally discovered in 1846, [music] Neptune was found exactly where scientists had expected. NASA's Voyager 2 spacecraft arrived in 1989, [music] many years and technological advancements later, zooming past Neptune, the last stop on a grand tour of the outer planets.

[00:04:59]We got a close-up view of a gorgeously [music] blue globe, its moons, and its rings during the flyby.

[00:05:07]Undoubtedly, [music] Neptune has rings.

[00:05:10]Although not as beautiful as Saturn's, they do exist and were created [music] from tiny rock and dust fragments. Since then, no spacecraft has landed on Neptune because Uranus is closer and would [music] be easier for our space robots to reach, planetary scientists recently recommended choosing one ice giant over the other to NASA.

[00:05:31]Exploring planets [music] that take so long to orbit the sun, 84 years for Uranus and an incredible 165 [music] years for Neptune, presents such a challenge.

[00:05:43]Undoubtedly, [music] a focused mission to Uranus that launched in the early 2030s would increase our knowledge of both ice giants. That, however, does not truly give Neptune its due. [music] The final planet in the solar system has a unique history and peculiarities that are fascinating and [music] enigmatic in and of themselves and deserving of our focused attention.

[00:06:07]A series of Hubble Space [music] Telescope observations of the giant planet Neptune reveals that a massive dark storm raging [music] in its northern hemisphere was moving south when it suddenly made a sharp U-turn and started moving [music] back north. In addition, it might have given birth to a young dark storm in the process.

[00:06:28]The term ice giant [music] refers to Neptune, which is essentially a huge ball of hydrogen and helium gas that also contains a lot [music] of methane, ammonia, and other molecules. For historical reasons, [music] planetary scientists still refer to these molecules as ices, even though they are gaseous. Neptune is the [music] largest planet that is the furthest from the sun at a distance of 4.5 billion kilometers, approximately [music] four times the diameter of Earth.

[00:06:58]Scientists were shocked by the [music] images Voyager 2 returned after passing by Neptune in 1989. It revealed a massive [music] oval dark storm the size of Earth in the planet's southern hemisphere, the Great Dark Spot, [music] so named because it had the fastest wind ever recorded in the solar system. It had wind speeds of a staggering 2,100 [music] kilometers per hour.

[00:07:23]But the spot was gone when Hubble observed Neptune [music] in 1994.

[00:07:28]Poof, disappeared. There is no doubt [music] that Neptune's storms develop over shorter periods than those on Jupiter, where the Great Red Spot has endured [music] for centuries, at least.

[00:07:40]For instance, a smaller dark patch in Neptune's southern hemisphere was [music] discovered in the same 1994 Hubble observations. This dark spot must have formed between the Voyager flyby and the Hubble photos. Since then, Hubble has discovered several more black spots. They develop at mid-latitudes in both hemispheres and tend to move in the direction of the equator, but they face certain death if they do that.

[00:08:08]As a result of the Coriolis effect, which states that the speed of a planet's rotation varies with latitude, with a maximum at the equator and a minimum at the poles, air flowing outward from a large high-pressure system or inward toward a low-pressure one will cause the system to begin rotating as it meets air moving at different speeds to the north and south.

[00:08:31]As these Neptunian storms move in that direction, the Coriolis influence weakens closer to the equator, which causes them to fragment. The majority of these storms appear to end up there.

[00:08:44]>> [music] >> Not this time. In September 2018, Hubble observed a mysterious storm in Neptune's northern hemisphere. The entire continental United States could easily fit inside this enormous, over 7,000 km wide object, which was seen to be traveling [music] south.

[00:09:03]However, inspections made in January 2020 [music] revealed that the storm's southern movement had been reversed and was now once more headed north. Neptune [music] is a mystery to scientists who study it. But there's more. This storm has been linked to two further strange occurrences. One is that it seemed [music] to have created a smaller dark storm at the time it changed its mind and began moving north [music] again.

[00:09:28]This is predicted to occur by some computer simulations of Neptune's atmosphere, particularly as a large storm [music] begins to dissipate towards the equator when it can drop smaller vortices.

[00:09:41]Although it wasn't directly [music] observed since the observations were spaced too far apart, it's possible that this is what happened in this instance.

[00:09:50]It may have shifted course due [music] to that, according to certain theories.

[00:09:54]Strangely, unlike almost every other dark [music] storm, this one doesn't have bright white clouds circling its edges.

[00:10:02]These methane ice [music] crystal clouds are highly reflective and appear white in photographs. Winds carry methane gas up the slopes of the dark storm's [music] high-pressure system, which resembles a mound of air in the atmosphere. Here, the [music] methane cools and crystallizes into ice. Orographic clouds, [music] which occur when water-rich air pushes up the side of a mountain, cools, and condenses to create clouds, [music] are typical on Earth. Images from 2019 showed the Neptunian white clouds, but they vanished at the beginning [music] of this year.

[00:10:37]The strange behavior of the black storm might be related to this, or maybe not.

[00:10:43]Due to its distance, Neptune [music] is challenging to observe and comprehend.

[00:10:47]And despite its enormous size, [music] it still appears very small in our telescopes.

[00:10:53]Additionally, [music] it is challenging to understand what's happening there due to the atmosphere's rapid changes.

[00:11:02]Neptune also has Triton, a planet-sized world with a smooth, icy surface, which it stole from a nearby region millions of years ago. Triton is one of the most fascinating moons in the solar system.

[00:11:15]As was previously mentioned, Voyager 2 sent back its sole close-up image to us in 1989, but this year, JWST focused on the far-off planet, [music] sending back some of the best images of its moons and rings that we've seen in the past 30 years.

[00:11:33]Methane, ammonia, [music] and water are among the several chemicals found inside Neptune. [music] However, because methane also absorbs infrared light, Neptune appears relatively faint in JWST [music] images.

[00:11:47]Methane is very good at absorbing red light, giving [music] the planet an icy appearance of a rich blue.

[00:11:54]It does, however, [music] have methane ice clouds at high altitudes, which, in contrast to [music] the gaseous form, are highly reflective and appear bright.

[00:12:04]Similar to storms on Jupiter, they appear at various [music] latitudes above the deeper cloud deck.

[00:12:11]Neptune has several rings, just like the other three giant [music] planets. These rings are probably made of ice particles that have been covered [music] in different molecules that give them a reddish appearance.

[00:12:23]This makes them brighter [music] in infrared wavelengths and makes them visible in the JWST image.

[00:12:30]You can also see Neptune orbiting a dozen minor moons. Proteus is a little over 400 [music] km in diameter.

[00:12:38]While most are small and irregularly shaped, measuring under [music] 200 km in width. As you can see, several of them are superimposed [music] on the rings.

[00:12:49]These are known as shepherd moons because it is suspected that Despina and Galatea's gravity may help to condense [music] the adjacent ring particles into little bands.

[00:13:00]What about that stunning teal star?

[00:13:02][music] Actually, that's Triton, mentioned earlier, the biggest moon of Neptune. At 2,700 km wide, it is slightly wider [music] than our own moon at 2,700 km, but larger than Pluto. The lines running [music] through it are diffraction spikes, which are produced when light bends around the three legs holding the secondary mirror of the JWST together, as well [music] as the hexagonal shape of its component mirrors. It appears bright because [music] it is covered in frozen nitrogen, which is highly reflective. A larger source, [music] such as Neptune, also has them, but they are smeared out and appear much fainter, [music] making them difficult to see. Only when the light source is very small in an image, what astronomers [music] refer to as a point source, can you get them this obvious. Appear much [music] fainter, making them difficult to see. Triton is an oddball. It orbits Neptune [music] backward in relation to the planet's rotation, leading astronomers to hypothesize that it might be a sizeable Kuiper Belt object that was long ago drawn in by the planet's gravity.

[00:14:09]It's challenging to accomplish this, and the precise method in this instance is unknown.

[00:14:16]In this up-close [music] view of Neptune, the clouds and rings are more clearly visible, along with some of their fainter [music] inner rings. It's interesting to see that a very thin, faint line circles [music] the planet only around its equator.

[00:14:30]The circulation in Neptune's atmosphere [music] moves from the poles toward the equator, where the gases sink and warm up, making it very dissimilar to our atmosphere.

[00:14:39]This weak arc might be warmer [music] gas that is heating up and emitting infrared light.

[00:14:46]Neptune and Triton may be seen in this breathtaking [music] wide-angle view once more.

[00:14:52]But this time, practically everything else in the picture is a background galaxy that is hundreds of millions, or possibly billions of light-years away.

[00:15:02]It serves as a poetic reminder that Neptune is the solar system's [music] final major colony.

[00:15:09]Since an orbiter could spend [music] years first at Uranus before moving on to orbit Neptune, scientists are very [music] interested in developing a mission specifically designed to explore the outer planets.

[00:15:22]Sending a probe that stays [music] on a planet for a long time is the best way to learn about it, as we discovered with Cassini at Saturn. Features come and go, conditions shift, and perhaps most [music] significantly, when researchers uncover novel occurrences, they may direct the spaceship [music] to investigate more closely.

[00:15:41]While learning new things is crucial, a focused objective allows you to remain and possibly ascertain their origin.

[00:15:49]We also learned that lesson from the Voyager flybys.

[00:15:52]Seeing Neptune up close for the first time >> [music] >> allowed for discoveries like the dark storms.

[00:15:58]But, if we want to understand them, we need to go there again and again.

[00:16:03]So, are we ever going to Neptune?

[00:16:06]Obviously not with [music] astronauts, but rather with a spacecraft created exclusively to investigate the mysteries [music] of our eighth planet. The James Webb Space Telescope, the most recent space observatory in existence, is currently [music] watching the ice giant and should produce further, previously unobtainable information about the makeup of its atmosphere. However, it's [music] not the same as actually being in orbit. By that standard, we have no knowledge of Neptune and probably never will.

[00:16:37]A recent mission [music] plan for an orbiter to Neptune called for an initial launch in 2033 and an arrival in 2049.

[00:16:46]However, traveling to Uranus [music] first would mean delaying that time scale by at least 10 years.

[00:16:53]The bluest planet might not get a spacecraft companion until well into the 2050s.

[00:17:02]Thanks for watching another episode of Voyager. [music] While you're still here, make sure to click the video on your screen for more mind-blowing videos about space.