#AstroMiniBR: How big is the sky in Brazil?

Each week, TecMundo and #AstroMiniBR select the best astronomical curiosities produced by their collaborators Profile on X to share with you a little more of the extraordinary and fantastic world of astronomy. Check it out below!

#1: Brazil’s starry sky

Brazil has a vast land mass spanning almost 40 degrees of latitude, Provides very different views of the night sky in different regionsThese differences are mainly due to the geographic location of each location and the curvature of the Earth, which affects which constellations, stars, and celestial bodies can be seen on the horizon.

In addition, the difference in the length of day and night depending on latitude also changes astronomical observations and becomes more pronounced as we approach the tropics and equatorial regions.

For example, in the Fernando de Noronha archipelago in northeastern Brazil, northern hemisphere constellations such as Orion can be seen high in the sky in the early evening. In the Serra do Divisor in the far west, the constellations will be visible at the same time, but slightly offset from the horizon.

On Mount Roraima in the far north, the northern hemisphere constellations are more prominent in the night sky. On the other hand, in Arroio Chui in the far south of the country, Constellations in the southern hemisphere, such as the Southern Cross, are more prominent and well positioned.

At the same time, this contrast in the skyscapes in different parts of Brazil demonstrates the richness of astronomical observations in the country and how geographic location shapes our perceptions of the universe.

#2: How do you measure the brightness of a comet?

Photometry is an important technique in astronomy. used to measure the brightness of celestial objects such as stars, planets, and asteroidsWhen applied to comets, photometry allows astronomers to measure the light reflected by the comet’s coma (the cloud of gas and dust surrounding the nucleus) and tail.

These data are crucial to understanding the comet’s composition and activity, as the observed brightness can change as the comet approaches or recedes from the Sun, indicating processes such as the sublimation of ice and the release of gases.

By taking photometric measurements over time, scientists can plot light curves that show how the comet’s brightness changes during its orbit. These light curves provide the basis for determining the nucleus’ rotation, the rate of gas and dust production, and even predicting the comet’s future behavior, contributing to a broader understanding of the physical processes occurring in the Solar System.

#3: What defines the death of a galaxy?

The “death” of a galaxy is a fascinating phenomenon that occurs when it stops forming new stars, resulting in an aged and dormant galaxy. Galaxies are composed of large amounts of gas and dust that collapse under the force of gravity, causing new stars to form.

Once this gas source is exhausted or expelled, the star formation process slows down until it stops completely. If new stars do not form, the galaxy begins to lose its brightness. and many are becoming dominated by old, cool stars that have become white dwarfs, neutron stars, or black holes.

There are several ways this could happen: One mechanism is through interaction with other galaxies, where intense gravitational forces can cause gas to be expelled or to coalesce into stars at a higher rate, depleting the reservoir needed for future generations of stars; another process is called “quenching,” where energy from a supermassive black hole at the center of the galaxy heats the gas to the point where it prevents new stars from forming.

For billions of yearsThe galaxy, once vibrant and full of young stars, becomes a passive, quiet structure with little or no stellar activity..

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