5 astronomical trivia of the week #AstroMiniBR [25/06]

#1: Man went to the moon and discovered that we are too small.

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More than 50 years ago, man visited the Moon and the reports from astronauts are incredible. Apollo 8 was the first human mission to take a walk around the moon and back safely! In addition to the historic landmark for humanity, they also recorded the “birth of the Earth as seen from the Moon”. Yea! As the Sun and Moon rise and set in our sky, the Earth also rises and sets in other skies. Puts things a little more into perspective, doesn’t it?

#2: What does Astronomy have to say about retrograde planets?

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It’s just having the word “retrograde” on the networks that the collective anxiety goes wild! But what does it mean from the point of view of Astronomy that a planet is “backward”? Directly, it just means that the position apparent in heaven has changed, but that the real movement remains the same. Let’s understand. In the animation above we can see two parts: the upper part shows the apparent path of the planet in our sky and the lower part the actual movement of the planets. We can see that the moment Mars goes “backward” is actually the moment the Earth passes it in the movement of orbits around the Sun, causing this apparent loop in our sky. It is as if, in a race, runner A overtakes runner B. When overtaking, runner A will see runner B in front of him, beside him, and behind him, respectively.

In short, there is no real change in the movement of the planets at that “retrograde” moment.

#3: Galaxy without dark matter?

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Saying that a galaxy has no dark matter is like saying that they found a human being without any bones! Hahaha exaggerations aside, it is extremely unexpected to find a galaxy without dark matter. That’s because our knowledge of galaxy formation today relies heavily on dark matter. In 2018, when they found the galaxy candidate without dark matter, one of the main points raised was in relation to the real distance of this object. In astronomy measuring distances is not elementary. Basically, if the object were closer than it was measured in 2018, the discovery would fall and the galaxy would have dark matter as expected. What no one expected is that by measuring the distance again with more accurate instruments, they actually found that the galaxy is farther away! Want to learn more about this discovery and its implications? Check out this week’s news.

#4: How big are we in the Universe?

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Astronomy is the science that scientifically investigates the Universe! So you might think that everything you’re looking for is more than a few kilometers, right? Wrong. As chemistry and physics are the same everywhere in the Universe, Astronomy can also study atoms and molecules of objects thousands of light years away! Like? Through the light! Light carries the fingerprint of the chemical composition of objects. Want to know more about the biggest objects in the Universe? Check out this week’s column about it!

#5: What the eyes don’t see… astronomy thinks!

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Did you know that there is much more light than meets the eye? The concept is not so new. Do you know the “night vision goggles”? These glasses actually “see” at wavelengths our eyes cannot detect! In this case, infrared. Now, there is much more light than we can see, and each wavelength is associated with a different energy. Lengths more “red” are associated with less energetic processes, while more “blue” are associated with more energetic processes. Why is this interesting? Because observing at different wavelengths, astronomy can study different physical processes that are taking place!

Electromagnetic spectrum demonstrating the small visible range for humans.Source:  All Matter

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