New findings coming directly from NASA’s New Horizons spacecraft cleared on Wednesday that the temperature in Pluto is even colder than scientists already estimated. According to the data taken directly from the dwarf planet in 2015, this is the only world in our Solar System whose temperature is affected by solid molecules rather than only gas.

In the report published today by the journal Nature, the group of scientists explained that the temperature of a typical planet is affected by three different factors: the sunrays that reach the world, how much this one reflects or absorbs them, and the composition of the entire atmosphere that covers it. These three components form a great team that makes the planet able to concentrate the heat and keep it within.

When talking about the Earth, the researchers said that the rays coming directly from the Sun travel across the entire space and merely pass through the gaseous atmosphere. Some of them stay, but others are reflected and sent out to space. However, Pluto is a little bit different planetary object.

Pointed the fact that Pluto once was considered the ninth and furthest planet in our Solar System, the distance between the sun and the dwarf is so massive that its light doesn’t reach Pluto the same way as it does other planets. The rays are fewer, and those touching Pluto’s atmosphere don’t do it with the same intensity.

Temperature in Pluto, Haze covering Pluto, Pluto haze
It’s the first time NASA scientists talk about the multiple haze layers in Pluto’s atmosphere. Image credits: NASA

Furthermore, there are twenty different layers separating space from Pluto’s surface. Some of them are formed by simple gas, but others are made of pure haze  millions of solid-hydrocarbon molecules gathering and floating together  making the sunrays’ job of creating heat even harder than scientists already expected.

“It’s been a mystery since we first got the temperature data from New Horizons. Pluto is the first planetary body we know of where the atmospheric energy budget is dominated by solid-phase haze particles instead of by gases,” said the lead researcher Xi Zhang, of the University of California, Santa Cruz. “We believe these hydrocarbon particles are related to the reddish and brownish stuff seen in images of Pluto’s surface.”

Haze layers between space and Pluto’s surface

When the researchers performed all the due studies to calculate an approximated temperature in Pluto, they didn’t know anything about the existence of these haze layers. would

At the moment when the scientists started performing all the tests to estimate the amount of heat there was in Pluto, they said that the number was around minus 280 degrees Fahrenheit  the equivalent of minus 173 degrees Celsius.

The new information collected by NASA’s New Horizons spacecraft showed that the actual temperature in Pluto is around minus 333 degrees Fahrenheit  which would also be minus 203 degrees Celsius.

Temperature in Pluto, Haze covering Pluto, Pluto haze
Researchers believe that the hydrocarbon molecules might be related to the brow and red colors over Pluto’s surface. Image credit: NASA

Of course, previous data was obtained thinking that Pluto was covered only by a gaseous atmosphere like the other planets  generally composed of many elements, such as the nitrogen, methane and carbon monoxide.

Now, knowing that there are multiple layers of haze covering Pluto’s surface, it’ easier to perform different analysis and understand more about this dwarf planet.

Haze could obscure the planetary object

The researchers believe that a chemical reaction in the highest area of Pluto’s atmosphere  about 435 miles (700 kilometers)  between the Sun’s ultraviolet rays, nitrogen and methane molecules creates the million small hydrocarbon particles that are essential to the dwarf planet’s cold.

A very similar reaction is thought to happen in the upper atmosphere of Saturn’s biggest moon, Titan. However, the result is so brutal, it completely covers and obscures the surface of the natural satellite.

“This is kind of a new regime of the climate of planets,” Zhang, assistant professor of Earth and planetary sciences at UC Santa Cruz, told “We never saw this before.”

The haze in Pluto’s atmosphere does not only trap the solar energy. In fact, it reacts and sends them back to the outer space in the form of infrared radiation – which is simple heat.

Zhang said that the atmosphere might be composed of gas, but that doesn’t mean the gas temperature is “controlled by the gases themselves.” According to him, this temperature is actually “controlled by the haze particles.”

Further research has to be made

For some scientists, there’s still a long way to go. Some of them believe this new finding puts a match point to Pluton’s temperature. But others think there should be more research.

Temperature in Pluto, Haze covering Pluto, Pluto haze
Pluto. 3.6 billion miles from the sun, was initially considered as a dwarf planet in 2006. Image credit: NASA

Robert West, a scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, wrote in the accompanying “News and Views” of Nature that the case “is not yet closed.”

“For instance, there are no observational constraints on the composition of Pluto’s haze, which means that the authors’ calculated heating and cooling rates are highly uncertain,” West said. “Without constraints, modellers are free to consider many possible haze compositions that have a wide range of optical constants — quantities that characterize the optical properties of a material.”

It will be only a matter of time to see if this new discovery is entirely true. If Pluto’s haze does send the heat back to the outer space, Zhang said that NASA will be able in 2019 to know it thanks to the upcoming James Webb Space Telescope.

Source: Nature