Spring is in the air. Aside from cherry blossoms, new leaves on the trees and rising temperatures (perhaps in some places, but apparently not Toronto), that means that we have new students in the lab. One of those new students is Ariella Sapers and she is starting off her work with us by diving right in with this article on Pluto. As you'll see from her article, it's definitely not springtime for Pluto. The image she has chosen, shown above (Credit: NASA, ESA and G. Bacon (STScI)) the artist gives a a distinctively cold cast to their view of this dwarf planet and it's large moon Charon from the surface of one of the outer-lying moons.
By Ariella Sapers
I’m one of the many people that strongly believe Pluto needs to become a planet again. Even though the three characteristics that define a planet (is in orbit around the Sun, has sufficient mass to assume hydrostatic equilibrium (a nearly round shape), and has cleared its orbital pathway) make logical sense, there is no real logic needed for the Pluto lovers out there who are mad with this decision. Ever since Pluto was discovered by Clyde Tombaugh in 1930, it has been a beloved member of our Solar System. That is until 2006 when Pluto officially was demoted to a “Dwarf Planet,” due to the fact that it does not clear its orbital pathway. With that being said, there are mysteries and wonders about Pluto that are still being discovered to this day.
As we know, New Horizons flew by Pluto July 14th 2015 making it the first spacecraft ever to explore Pluto. I couldn’t have been the only one who woke up extra early to watch this flyby happen and I couldn’t have been the only one amazed by the images that we received on Earth. These images were breathtaking: being able to see an object 4.67 billion miles away from Earth in detail was quite an accomplishment for the New Horizons team. It was a huge leap for science as we would now be able to understand and learn more about Pluto’s atmosphere.
As we know, New Horizons flew by Pluto July 14th 2015 making it the first spacecraft ever to explore Pluto. I couldn’t have been the only one who woke up extra early to watch this flyby happen and I couldn’t have been the only one amazed by the images that we received on Earth. These images were breathtaking: being able to see an object 4.67 billion miles away from Earth in detail was quite an accomplishment for the New Horizons team. It was a huge leap for science as we would now be able to understand and learn more about Pluto’s atmosphere.
For me, I was just starting to learn more about the world of Planetary Science so I was excited to see what the next steps were to understanding more about Pluto’s atmosphere, and what techniques were used to discover more information. When the images were released, what was extremely special was the heart located on Pluto’s surface. The heart on Pluto’s surface is actually made of nitrogen ice and is one of the most geographically beautiful traits about Pluto. I found this very comical and ironic, since the planet that was just demoted to a dwarf planet has a heart on its surface, yet the heart is made of cold ice. There was something very poetic about it.
But Pluto is a lot more than just a dwarf planet with a heart, Pluto has a fascinating atmosphere that is actually in danger. With a technique called ground-based stellar occultation, the seasonal changes of Pluto have been observed. Occultations occur when some sort of object, usually a moon or planet or its atmosphere, blocks incoming light to Earth from a distant star. With this technique, you are able to learn more about that object, like the atmosphere's density, pressure and temperature.
With this technique being used, it was found that the nitrogen on Pluto’s surface is at risk. This was discovered using seasonal models of Pluto, constructed from these ground based stellar occultations. They showed that when Pluto is at aphelion from the Sun and during winter in the northern hemisphere, nitrogen is able to freeze out of the atmosphere. In order for Nitrogen to freeze, the temperature needs to get extremely cold, which makes sense for Pluto since the temperature on Pluto ranges from -228C to -238C. Pluto's temperature is this cold due to the fact that it is very far from the Sun.
Pluto has a very interesting orbit that is different than the planets in the solar system. Most of the planets in the solar system orbit a nearly flat plane in relation to each other, while Pluto was knocked out from this plane and its orbit tipped about 17 degrees in relation to the plane. Not only that, but Plutos orbit is highly elliptical, so the atmosphere will change over time. The atmosphere will expand and contract when the components in the atmosphere freeze, at aphelion, and melt, at perihelion. When thinking about Plutos orbit, we can use the term “eccentricity” to describe the orbit. If the eccentricity of an orbit is close to 0, it is a circle, anything larger is an ellipse. Pluto has an eccentricity of 0.25 while Earth is 0.02. It is because of these characteristics of Pluto that its distance from the Sun will vary from 4.4 - 7.4 billion kilometers and with Pluto's atmosphere being discovered during a time where it was approaching its closest distance to the Sun, it makes sense that as it retreats the temperature is decreasing.
It has shown that since 1988, Plutos atmospheric pressure has slowly been increasing due to the fact that its north pole is continuously being lit by the sun during its current place in orbit and the nitrogen ice cap is becoming a gas. It is because of this freezing temperature and the fact that Pluto’s atmospheric pressure has increased in the last 30 years, that by 2030, Pluto’s atmosphere will likely collapse. This will be because these models that have been created show that the atmosphere will condense outwards until nothing remains.
While most of this is a negative, there is one positive that would come from this, the result would actually be beautiful. If this was to happen, the freezing nitrogen will reflect more sunlight which will make Pluto appear brighter in the sky …. which I would be VERY happy about. It would definitely make us Pluto fanatics very happy. A negative of this would be that what we saw with the New Horizons spacecraft would be different. The colours that the spacecraft showed us, like the red terrain, would be hidden by the nitrogen frost. This would actually be very interesting to see and I'm sure that comparing those images in 2030 to the ones taken in 2015 would lead to some great scientific discoveries. But New Horizons is past Pluto, it actually flew by Ultima Thule January 1st 2019, so we will just have to wait till 2030 to see what happens!
At the end of the day, whether Pluto is a planet or not, there are many geographical and atmospheric traits about the dwarf planet that make it special. Studying the Martian surface has given me a new found respect for Planetary atmospheres - and Pluto is no exception!
The article about Pluto’s atmosphere freezing can be found at : https://www.digitaltrends.com/cool-tech/pluto-atmopshere-freeze/
But Pluto is a lot more than just a dwarf planet with a heart, Pluto has a fascinating atmosphere that is actually in danger. With a technique called ground-based stellar occultation, the seasonal changes of Pluto have been observed. Occultations occur when some sort of object, usually a moon or planet or its atmosphere, blocks incoming light to Earth from a distant star. With this technique, you are able to learn more about that object, like the atmosphere's density, pressure and temperature.
With this technique being used, it was found that the nitrogen on Pluto’s surface is at risk. This was discovered using seasonal models of Pluto, constructed from these ground based stellar occultations. They showed that when Pluto is at aphelion from the Sun and during winter in the northern hemisphere, nitrogen is able to freeze out of the atmosphere. In order for Nitrogen to freeze, the temperature needs to get extremely cold, which makes sense for Pluto since the temperature on Pluto ranges from -228C to -238C. Pluto's temperature is this cold due to the fact that it is very far from the Sun.
Pluto has a very interesting orbit that is different than the planets in the solar system. Most of the planets in the solar system orbit a nearly flat plane in relation to each other, while Pluto was knocked out from this plane and its orbit tipped about 17 degrees in relation to the plane. Not only that, but Plutos orbit is highly elliptical, so the atmosphere will change over time. The atmosphere will expand and contract when the components in the atmosphere freeze, at aphelion, and melt, at perihelion. When thinking about Plutos orbit, we can use the term “eccentricity” to describe the orbit. If the eccentricity of an orbit is close to 0, it is a circle, anything larger is an ellipse. Pluto has an eccentricity of 0.25 while Earth is 0.02. It is because of these characteristics of Pluto that its distance from the Sun will vary from 4.4 - 7.4 billion kilometers and with Pluto's atmosphere being discovered during a time where it was approaching its closest distance to the Sun, it makes sense that as it retreats the temperature is decreasing.
It has shown that since 1988, Plutos atmospheric pressure has slowly been increasing due to the fact that its north pole is continuously being lit by the sun during its current place in orbit and the nitrogen ice cap is becoming a gas. It is because of this freezing temperature and the fact that Pluto’s atmospheric pressure has increased in the last 30 years, that by 2030, Pluto’s atmosphere will likely collapse. This will be because these models that have been created show that the atmosphere will condense outwards until nothing remains.
While most of this is a negative, there is one positive that would come from this, the result would actually be beautiful. If this was to happen, the freezing nitrogen will reflect more sunlight which will make Pluto appear brighter in the sky …. which I would be VERY happy about. It would definitely make us Pluto fanatics very happy. A negative of this would be that what we saw with the New Horizons spacecraft would be different. The colours that the spacecraft showed us, like the red terrain, would be hidden by the nitrogen frost. This would actually be very interesting to see and I'm sure that comparing those images in 2030 to the ones taken in 2015 would lead to some great scientific discoveries. But New Horizons is past Pluto, it actually flew by Ultima Thule January 1st 2019, so we will just have to wait till 2030 to see what happens!
At the end of the day, whether Pluto is a planet or not, there are many geographical and atmospheric traits about the dwarf planet that make it special. Studying the Martian surface has given me a new found respect for Planetary atmospheres - and Pluto is no exception!
The article about Pluto’s atmosphere freezing can be found at : https://www.digitaltrends.com/cool-tech/pluto-atmopshere-freeze/
Nicely done. Informative and humorous
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