#AstroMiniBR: see the power of a supernova glow!

Every Saturday, the TecMundo and #AstroMiniBR bring together five relevant and fun astronomical curiosities produced by the collaborators of the profile on twitter to spread the knowledge of this science that is the oldest of all!

#1: An astronomical crustacean

Nearly a thousand years ago, in the year 1054, the sky over China took on a light unlike any commonly seen in the night sky at the time. Chinese astronomers called it a “guest star” that was, for almost a month, visible even during the day.

This light was actually the explosion of supernova that gave rise to Crab Nebula, a six light-year-diameter remnant of this cataclysmic cosmic event. The Crab Nebula is located 6,500 light-years from Earth and can be seen easily with a small telescope.

The remnant of this potent light was rediscovered in 1731 and was later observed by Charles Messier, who was inspired to create a catalog of celestial objects. The color of the image presented above gives us information about the chemical composition of the nebula: the orange filaments represent the structures of plasma and stellar gas, composed essentially of hydrogen; the blue tones on the outer filaments represent oxygen; and green represents ionized sulfur.

All these elements were ejected in a very violent way during the explosion of the supernova that left as a dying star, a small neutron star at its center that rotates rapidly about 30 times every second!

#2: The Hubble Space Telescope’s Myopia

When the Hubble Space Telescope (HST) was launched in 1990, one of the golden ages in astronomy began. The telescope opened the windows of the Universe for humanity and made possible an unprecedented understanding of the Cosmos. However, not all stages of this journey were flowers in these 32 years of activity of the HST.

Shortly after its launch into Earth orbit, scientists discovered that its main mirror was incorrectly grounded, which caused spherical aberration that greatly compromised the telescope’s capabilities.

A maintenance mission in 1993 fixed the problem, correcting the optics and adjusting the intended quality. Since then, a total of five space missions have made repairs, upgrades and replacements of the telescope’s systems and parts, including most of its main instruments. The last one took place in 2009 and significantly extended the telescope’s life, expected to last another decade or two.

#3: An empty spot in the middle of the galaxy?

That black holes are one of the most impressive and powerful celestial objects in the Universe we know. However, we rarely have the opportunity to see one in action, precisely because we can only observe its indirect effects.

The video above showcases the awesome power of gravity from the central supermassive black hole that is hosted at the center of our galaxy! The European Southern Observatory’s (ESO) Very Large Telescope (VLT) located in the Chilean desert has been observing the supermassive black hole at the center of our galaxy and the stars that orbit it.

Using observations from the last 20 years, ESO has compiled observations of the S2 stars orbiting the monstrous hole that has the mass of four million suns put together! At the closest points, some stars came within 20 billion kilometers of the black hole and were moving faster than 25 million kilometers per hour, which is about 3% of the speed of light!

#4: How bright is a supernova?

NGC 4647 or Messier 60 is the name given to an intermediate spiral galaxy that is located in the direction of the constellation Virgo, about 63 million light-years away from Earth. Discovered in 1784, NGC 4647 is part of a pair of interacting galaxies known as Arp 116. NGC 4647 presents typical characteristics of a spiral galaxy and would, in principle, be unsurprising, going unnoticed even by astronomy enthusiasts, were it not for the fact that of having recently presented a relatively rare spectacle: the brightness of a type Ia supernova — one of the most energetic and violent events in the Universe — that is comparable to the total brightness of the host galaxy itself!

#5: How do galaxies form?

It is not possible to follow the formation and evolution of a single galaxy (or a planet or star) due to the huge difference between our lifetime and the “lifetime” of galactic objects. However, observing a sufficiently large number of celestial objects in different evolutionary stages and adding to the known laws of physics, allows the construction of theoretical models that cover much of the puzzle of cosmic history. For this, simulations, like the one presented in the video above of IllustrisTNG “evolving” a galaxy, are fundamental to help astronomers obtain and test scientific hypotheses!

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