Why is Neptune’s moon Triton so strange?

In fact, astronomy is largely similar to a forensic investigation in its functioning. Just as we cannot recreate what happened at a crime scene, I cannot recreate past events in astronomy. So how are the unknowns found in forensic medicine? Thanks to the little clues left at the scene, of course. In order to understand the events in the farthest corners of space, astronomy studies the crime scenes. In fact, we don’t have to look very far for a crime scene. Neptune in the outer reaches of our solar system and Triton orbiting it contain a mysterious crime scene. So how did Neptune have a moon like Triton?

Neptune and Triton

Neptune has 14 known moons. Except for Triton, all of Neptune’s moons are very small and fall into two general groups: regular and irregular. While regular ones orbit close to the planet, irregular ones are generally farther from Neptune and orbit in a variety of orbits.

And then there’s Triton, discovered by English merchant and amateur astronomer William Lassell. Triton was detected in 1846, just 17 days after the discovery of Neptune. The first close look at this mysterious satellite was taken with Voyager 2, 143 years later, on August 25, 1989. Although Voyager 2 mapped only 40 percent of Triton’s surface, the mission was enough to reveal just how strange the Neptunian moon is.

The first thing you need to know about Triton is that it is pretty big. The seventh largest moon in the solar system, Triton is 200 times larger than all of Neptune’s other moons combined, making it truly remarkable.

The second thing you need to know is that Triton is one of the irregulars. It orbits in reverse relative to Neptune’s rotation, and its orbit is inclined at a surprising 67 degrees – nearly perpendicular to its home planet. The satellites of some planets in our system also rotate in the opposite direction of the main planet. But none of them are as big as Triton. The largest of these, Phoebe (Saturn), has only 8 percent of Triton’s diameter (and 0.03 percent of its mass). Despite its irregularity, Triton’s orbit is surprisingly circular—in fact, it has one of the most perfectly circular orbits of any body in the Solar System.

Triton’s surface actually resembles a melon. Much of Triton’s mid-latitudes is covered by rugged, rugged features called melon terrain. While a large part of the moon contains vast, shapeless plains dotted with huge calderas, the southern part is dominated by a vast nitrogen ice cap dotted with dozens of water-spewing volcanoes.

Triton’s surface also doesn’t have many craters, indicating that the moon has the ability to resurface and seal craters. This is a rare feature in the solar system and indicates that Triton is still partially hot. Of course, this temperature is related to the inside, the outer surface is approximately -253 degrees. So it’s even colder than the outermost Pluto.

Identification of suspects

We’ve pieced together the hard facts from the scene: Triton is much larger than it should be, has a completely strange orbit, formed in an unconventional way, and has a young, dynamic and active surface.

So what is the story behind these oddities? The best answer is that Triton is not an ordinary satellite, but may have been the victim of an interplanetary “hijacking” event. Triton may be a Kuiper Belt object, perhaps more similar to Pluto or Eris than to other moons of the Solar System. Perhaps long ago, Triton may have crashed near Neptune, been captured by the planet’s gravity, and remained trapped there for the remaining billions of years.

Either Triton got unlucky and had exactly the wrong orbit to come close to Neptune, or it collided with one of Neptune’s original moons and became stuck in orbit in the process. Another possibility is that Triton, like many other Kuiper Belt objects, formed as a small binary system, and in a close encounter with Neptune, Triton’s twin flew away, leaving Triton trapped.

The fact that Triton is caught in Neptune’s orbit also explains its strange orbit. The reason why Triton remains hot may be because it has enough radioactive elements to emit heat, like Kuiper Belt objects. This heat may have turned water, carbon dioxide and nitrogen ice into slush, keeping the surface young and active, just like on Pluto. In fact, Triton may be so hot that it may harbor an ocean of liquid water beneath its crust.

It has been 34 years since we last saw Triton up close. Unfortunately, no missions are currently planned to return to the Neptune system. NASA is focusing on the Jupiter and Saturn systems in its future programs. Actually, this makes sense because there are moons around both planets that are thought to have liquid water. And they are much, much closer than Neptune.

Therefore, there is a possibility that we will not see Neptune and Triton as a follow-up in our lifetimes. Therefore, it looks like it will take decades for this crime scene to be fully discovered. But don’t worry, we have plenty of time before Triton disappears (yes, it will disappear soon). Scientists estimate that in approximately 3.6 billion years, Neptune will pass below the Roche limit and break up.