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We are now in a new era of space exploration, where distant planets (called exoplanets) are being discovered at a rapid clip. At last count, there are 5,557 confirmed exoplanets and another 10,000 candidates awaiting confirmation. These studies have given rise to “planetary comparison,” a new field of astronomy devoted to the study of the properties of different worlds, classifying them according to size, mass, (approx. ) the composition of the atmosphere, distance from their parent stars, and whether they are rocky. , gas, or a combination of the two.
The main goal is to compare Earth with other planets in our Solar System. For example, when astronomers talk about a “super-Earth,” it means a rocky planet with a diameter greater than Earth, while a “sub-Neptune” is a planet gas and its radius is smaller than Neptune. These definitions are used and the boundaries between planetary classes are not very rigid, but they offer a quick way to classify what we see.
Planetary comparison
Exoplanets are planets that orbit other stars in our galaxy (and stars in other galaxies too, but those are too far away to see). The M-type dwarf star (or red dwarf star) is the smallest and most faint star, the most common star in the Milky Way. About three-quarters of the stars in our galaxy are M-type stars. In comparison, our Sun is a yellow dwarf star, about five times larger than the red dwarf. Only 3% of stars are as yellow as our Sun.
The differences in planetary systems are quite surprising. There is no obvious or common type of planet: Some have giant planets like Jupiter orbiting close to their host stars, while others have more widely distributed planets, and some look similar to our Earth. These seem to be very rare.
If you are not amazed by what astronomers have discovered about planetary systems, consider how difficult it is to find distant planets. Finding a planet orbiting another star is a lot more difficult than finding a feather in front of a floodlight. To detect them, astronomers capture the faint dimming of starlight as a planet passes in front of a star. This is called the transit planet. Imagine measuring the lawn of a floodlight as a flea jumps up. Now, move the floodlight away – make it look like a source. With this image, you begin to get an idea of the sensitivity and wonder of finding exoplanets.
The main reason, of course, is to think about how rare or common our planet is. If there are many planets like the Earth – not only the same size and composition, but also located in the so-called “seat zone” which is the star of water, if it is in on the planet, it will be fluid – then difficult. the more advanced those worlds can have a form of life. Like my Dartmouth friend Elisabeth Newton reported several years ago Reflecting on his discovery of a distant planet orbiting a small star, “One of the universal goals of astronomy is to understand the big picture of how we came to be.” here, how the sun and galaxies evolved and why. By exploring solar systems other than ours – especially young ones – we can hope to learn why the Earth and our Solar System evolved the way they did.
So, everything comes down to one of the most interesting questions that we can ask in science – the one children from five to 90 years old ask in all cultures on our planet: Are we alone in the Universe? Studying other worlds – their history, places, and properties – allows us to know our own history, and how unique (or not). We live in this special time where we can really begin to answer this question. And it all points to it our planet is a rare gem in a Universe so hostile to life.
We are still far from knowing if there is life on other worlds. Obviously, since there are many worlds out there (trillions in our galaxy alone), and the laws of physics and chemistry are the same in the universe (that we know for sure), the hope from a large group of scientists. is: Yes, there must be other worlds and life. Otherwise, it’s like Jodie Foster’s character in the movie Get in touch (based on the accompanying story by Carl Sagan) said, “(It) seems like a terrible waste of space.”
But life is not as simple as big numbers. There is a disconnect between the way physical scientists and biologists think about this question. (Of course, there are exceptions to both categories.) Biologists tend to be more cautious about such statements, knowing that life is very complicated. There are many really complicated steps that go from lifeless to the first living things, and then to the complex unicellular life and multicellular creatures. What’s more, life without a plan gets more complicated over time; Life is concerned with good reproduction. If the species are well adapted, the changes will not have much effect. Finally, the question of how life appeared on earth remains open.
The “symbol of life”
What we know now, and it is very important, is the life history of a planet – the details of how it came to be, from its atmosphere to the effects of space and seismic – of written on his creatures. And vice versa: Life changes its host planet in amazing ways. There is a two-way relationship between the history of the planet and the type of life it supports. The planet provides the main support for life so that life can and will move on the planet and change it. The world today is a different planet than it was three billion years ago, when there were only single-celled organisms. Their action changed the planet by increasing the level of oxygen in the atmosphere. Without that, we wouldn’t be here. We can also see this in our own destructive actions, and how they are imprinted on the world. The existence of people has permanently scarred the world.
Popular brands can change their world, whether they know it or not. We live in the truth of this fact. However, many of us choose not to pay attention or change our ways. Disconnected from nature, we seem to have forgotten how much our lives depend on it. Bad water + bad air = sick life. That’s the equation everyone should know – it’s called the “survival equation.” Perhaps what we have learned about our planet and its distant cousins will inspire us to rethink how we relate to our world and the creatures we share it with.