#AstroMiniBR: Why do stars appear to shine in the night sky?

Every week, TecMundo and #AstroMiniBR bring together the most relevant astronomy curiosities produced by collaborators From Twitter profile Spreading the knowledge of one of the world’s oldest sciences. See below!

#1: Stars twinkling

Although when we look at the night sky we get the impression that countless stars are twinkling their light, this is not what actually happens. The phenomenon that causes stars to appear to “twinkle” in the night sky is known as atmospheric twinkle. It is an optical process caused by the interaction of starlight as it passes through various layers of the Earth’s atmosphere.

As starlight passes through these layers, it is refracted by changes in air density, temperature and pressure. These fluctuations, although relatively small, are significant and slightly alter the path of light between the object and the observer, creating a twinkle effect characterized by the apparent change in the light intensity of the star. This phenomenon is especially evident when we observe stars close to the horizon, where light must travel a greater atmospheric distance.

Astronomers often use the intensity of scintillation to study atmospheric turbulence and develop techniques to correct distortions in astronomical observations made with modern instruments.

#2: Fantastic passage of a comet!

Comets have been mysterious space travelers for thousands of years. Today our understanding is broad enough to know that these are actually rocky celestial bodies with elliptical orbits of high eccentricity, composed largely of ice, dust, and gases.

When one of these objects approaches our solar system’s central star in orbital orbit, the intense heat causes its volatile components to sublimate, creating a spectacular coma, a kind of diffused atmosphere, around the core. Additionally, comets have a long, prominent tail that always points away from the Sun due to solar wind pressure and radiation.

Comets have fascinated observers throughout history and they are crucial to understanding the original composition of the solar system, as they preserve traces of the beginning of our cosmic home.

The visibility of comets depends on their proximity to Earth, and many comets are visible to the naked eye. In the footage above, you can see the distinctive tail of Comet Nishimura, discovered this year, formed by the interaction of the comet and the solar wind. These observational features not only provide an unforgettable celestial view, but also provide valuable data for scientists to better understand the orbital dynamics of the solar system’s small bodies.

#3: Do you know what an analemma is?

Analemmas are fascinating celestial figures that emerge from a projection of the Sun’s daily positions in the sky over the course of a year. Visually, they take the shape of a figure eight, often described as a “waist” that narrows and widens. This peculiar pattern results from a combination of changes in the tilt of the Earth’s axis and the planet’s elliptical orbit around the Sun.

Over the course of a year the Sun appears to move back and forth, creating this interesting pattern when all of its positions are recorded and connected. Analemmas are an elegant visual representation of the complexity of the orbital motions that govern our solar system. and offers a unique view of the dynamic interaction between the Earth and the Sun.

These image formations not only fascinate astronomers, but also have practical implications. For example, analemmas can be used to correct inaccuracies in sundials throughout the year. Additionally, they provide a vivid visual understanding of seasonal changes, highlighting the connection between celestial geometry and weather patterns on Earth.

All this makes analemmas not only astronomical curiosities, but also valuable tools for understanding the relationship between our planet and the Sun, the central source of its light and energy.

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