Free Republic

Betelgeuse is our next door supergiant. It is almost 1000 times bigger than our sun and possibly it has already exploded in a giant supernova. How would we notice, how fast would the process be and what could we expect to see from Earth? Something happened in 2019 Betelgeuse is currently in the final stages of its short life. So when the red supergiant abruptly darkened in late 2019, the behavior led many to speculate that it might be about to explode. The loss of brightness was far greater than anything previously recorded. Analyzing data from Hubble Space Telescope and...

The visible surface of the Sun, or the photosphere, is around 6,000°C. But a few thousand kilometers above it – a small distance when we consider the size of the Sun – the solar atmosphere, also called the corona, is hundreds of times hotter, reaching a million degrees celsius or higher. This spike in temperature, despite the increased distance from the Sun’s main energy source, has been observed in most stars, and represents a fundamental puzzle that astrophysicists have mulled over for decades. In 1942, the Swedish scientist Hannes Alfvén proposed an explanation. He theorized that magnetized waves of plasma...

Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2002 November 14 The Sharpest View of the Sun Credit: SST, Royal Swedish Academy of Sciences Explanation: This stunning image shows remarkable and mysterious details near the dark central region of a planet-sized sunspot in one of the sharpest views ever of the surface of the Sun. Just released, the picture was made using the Swedish Solar Telescope now in its first year of operation on the Canary...