How many galaxies are there in the Universe? Week #AstroMiniBR

every saturday, the TechWorld and AstroMiniBR bring together five relevant and fun astronomical curiosities produced by the contributors to the Twitter profile to disseminate knowledge of this science, which is the oldest of all!

This week, we have a multitude of galaxies, expanding universe, the largest reservoir of water there is, beautiful images of the Moon, and the future of the Solar System. Come on?

#1: The universe is much bigger than you think!

Between September 2003 and January 2004, the Hubble Space Telescope aimed at a tiny region in the sky, so small that its size is only one-tenth the diameter of the full Moon when viewed from Earth. The reason the observation was made is that this was an apparently “empty” region in the sky, with a low density of stars and, to put it simply, astronomers wanted to know what would be there if there was enough time. of observation. The result was astonishing: around 10,000 galaxies appeared where nothing but emptiness seemed to exist. This image became known as the Hubble Ultra Deep Field (Hubble Ultra Deep Field). This is the deepest image ever taken of the Universe in the visible spectrum and shows only a very small portion of the 200 billion galaxies estimated to exist! This number, however, could be even higher: the upper limits of some estimates indicate that the Universe could house around 2 trillion galaxies!

#2: And how long has there been such a big thing?

Since the discovery that the universe is expanding in 1927 and 1929 (two independent discoveries made by astronomers Georges Lemaître and Edwin Hubble, respectively), it has been well known that, on average, distant galaxies move further and further away from each other. as time goes by. What would happen, then, if this movement were seen in hindsight? It was a similar question to this that generated the first thoughts of what is now known as the Big Bang Theory, which in turn is related to a standard model of how the universe works, called the Lambda-CDM model. lambda cold dark matter). Now, if the galaxies move further and further away from each other, at some point in the past they were much closer than they are today. If that movement is traced back to time zero, that would be the instant when everything got started. It is understood that this moment occurred about 13.8 billion years ago, which is precisely the age of the Universe!

#3: What is the biggest water reservoir there is?

You were wrong if you thought about the oceans of our planet Earth. If you’re an astronomy enthusiast and you thought that the biggest reservoir of water lies beneath the ice sheets of Ganymede, the distant moon of Jupiter, you were wrong too. The largest reservoir of water ever discovered in the Universe is located in an unusual place: the distant quasar APM 08279 + 5255, a bright and violent region in space fed by a supermassive black hole at its center. This huge reservoir, 12 billion light-years away from us, is in the form of water vapor and corresponds to at least 140 trillion times the amount of water in all of Earth’s oceans combined. That’s about 20 billion times more massive than our Sun!

#4: The Moon in False Color Images!

These images were taken in December 1992 by the Galileo spacecraft as it was heading towards its final destination, the orbit of Jupiter. When these records were made, the probe was 425,000 kilometers from the Moon and just 69,000 kilometers from Earth. Images were combined and processed with false colors to enable a better understanding of the characteristics of the lunar surface. Areas that appear in red generally correspond to higher lands in relation to the ground, while shades of blue and orange indicate the ancient volcanic lava flow of the Moon Seas. The Sea of ​​Tranquility (mare tranquillitatis), landing site of the Apollo 11 Lunar Module on July 20, 1969, is seen as a dark blue spot above right in image 2 and below left in image 1.

#5: What will be the future of the Solar System?

Low-mass stars like our Sun do not end their life cycle in gigantic thermonuclear explosions known as supernovae. Instead, your future is relatively quieter and less dramatic. In the last billion years of the Sun’s life, several changes will occur in its structure, from the lack of hydrogen in its core to burn to its growth into a red giant star. In its last breaths, the Sun will eject its outermost layers into space until it forms a planetary nebula: a structure with glowing layers of plasma and white dwarf remnant at its center, which will slowly cool down until it completely fades.

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