After flying over Pluto and obtaining images of its surface with an unprecedented level of detail, the New Horizons probe continues its journey to the ends of the solar system with the aim of studying other transneptunian objects, often referred to as TNOs, for its acronym in English.
TNOs are considered the celestial bodies that orbit the Sun to more than 30 astronomical units (AU), the average distance that separates the Sun from Neptune and amounts to 4.5 billion kilometers. The objects that have been discovered so far in this region of the solar system have very different sizes. A few are similar to Pluto and exceed a thousand kilometers in diameter, such as the dwarf planets Eris, Makemake or Haumea, but the vast majority of the more than 2,500 TNOs that have been cataloged have diameters that range between a few tens of kilometers and several Hundreds
Distant worlds of ice and rock
Although the existence of thousands of celestial bodies this large in the confines of the solar system can be shocking, the truth is that the known TNOs represent a tiny fraction of all that could exist in this region. These objects form two “rings” around the Sun: the so-called “Kuiper belt”, which extends from 30 to 50 AU of our star, and the “scattered disk”, which covers the region between 30 to 100 UA. To give an idea of the number of TNOs that exist, it is estimated that only the Kuiper belt could house more than 100,000 objects with a diameter greater than 100 kilometers and millions of smaller bodies.
The TNOs are very different from the inner rocky planets, which have a dense metal core surrounded by a blanket of rock. The reason is that, having formed so far from our star, these objects are mainly composed of rock and frozen volatile substances, such as water, nitrogen, ammonia and a wide variety of organic compounds. The largest bodies in this region have a rocky core covered by a blanket of frozen material, but the smaller ones do not have a gravitational field intense enough for their interior to have differentiated and its structure is a more uniform mixture of ice and rock.
This high content of volatile compounds prevents the existence of TNO-like bodies in the inner solar system, where the heat of our star would vaporize them. In fact, comets exemplify very well what would be the fate of a TNO that would get too close to the Sun, since many comets are objects of the scattered disk that go into the inner solar system after their orbit is disturbed. As these masses of ice and rock approach our star, volatile substances on their surface heat up, vaporize and escape into space forming a characteristic “tail” of gas. In this way, comets lose mass until they disintegrate.
The future home of humanity?
Since TNOs can only exist in the cold confines of the solar system, at first glance it does not seem that these icy bodies are a good place to establish a human colony … But that impression could be wrong.
At the end of the day, these objects have large amounts of volatile frozen substances (such as water, nitrogen or different organic compounds) that are very useful both for life and for manufacturing fuel and it is believed that some dwarf planets in this region could even reach to house oceans of liquid water beneath its surface. In addition, digging an underground base in which to shelter from the inclemency of space would be a much simpler task on the frozen ground of one of these frozen objects than on a rocky planet. In fact, Kenneth I. Roy et al They concluded that it would be possible to “empty” these small celestial bodies, fill their inner space with gas and colonize their inner walls.
Of course, colonizing the Kuiper belt or the scattered disk at these scales would require amounts of energy at magnitudes that cannot be obtained in the dark outside of the solar system. This problem could be solved temporarily by transporting nuclear fission generators from the inner solar system, but, over time, the development of devices that produce energy through the fusion Nuclear power of hydrogen, a very abundant element in this region of space, should provide more than enough energy to these hypothetical colonies to convert the millions of frozen objects from the confines of the solar system into relatively cozy homes … Or, better yet, in the bases that will allow us to make the leap to the stars.
DON’T KEEP IT UP:
- Pluto was not classified as a “dwarf planet” on a whim. After the discovery of other objects with orbits, compositions and sizes similar to those of Pluto in the confines of the solar system, everything indicated that it was another class of celestial bodies that shared common characteristics.
- Steve Vance et al. “Hydrothermal systems in small ocean planets”, Astrobiolgy. Volume 7, number 6 (2007).
- Lists of trans-Neptunian objects, Wikipedia:
- Kenneth I. Roy et al. “Shell Worlds”, Journal of the British Interplanetary Society, volume 62, number 1 (January 2009).