supernova is the biggest explosion
A supernova is the biggest explosion that humans have ever seen. Each blast is the extremely bright, super-powerful explosion of a star.
What causes a supernova?
One type of supernova is caused by the “last hurrah” of a dying massive star. This happens when a star at least five times the mass of our sun goes out with a fantastic bang!
Massive stars burn huge amounts of nuclear fuel at their cores, or centers. This produces tons of energy so the center gets very hot. Heat generates pressure, and the pressure created by a star’s nuclear burning also keeps that star from collapsing.
A star is in balance between two opposite forces. The star’s gravity tries to squeeze the star into the smallest, tightest ball possible. But the nuclear fuel burning in the star’s core creates strong outward pressure. This outward push resists the inward squeeze of gravity.
Various civilizations recorded supernovae long before the telescope was invented in the 17th century. The oldest recorded supernova is RCW 86, which Chinese astronomers spotted in A.D. 185. Their records show that this “guest star” stayed in the sky for eight months, according to NASA.
arguably the most famous supernova, was first spotted by Chinese and Korean astronomers who recorded this star explosion in their records in 1054. Native Americans may have seen it as well, according to rock paintings found in Arizona and New Mexico. The supernova that formed the Crab Nebula was so bright that those early astronomers could see it during the day
On average, a supernova will occur once every 50 years in a galaxy the size of Milky Way, according to research by the European Space Agency. This means a star explodes every 10 seconds or so somewhere in the universe, according to the U.S. Department of Energy
Let’s look at the more exciting Type II first. For a star to explode as a Type II supernova, it must be several times more massive than the sun (estimates run from eight to 15 Solar masses Like the sun, it will eventually run out of hydrogen and then helium fuel at its core. However, it will have enough mass and pressure to fuse carbon.
Next, gradually heavier elements build up at the center, and the star forms onion-like layers of material, with elements becoming lighter toward the outside of the star. Once the star’s core surpasses a certain mass (called the Chandrasekhar limit), it begins to implode. For this reason, these Type-II supernovae are also known as core-collapse supernovae.
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Eventually the implosion bounces back off the core, expelling the stellar material into space, forming the supernova. What’s left is an ultra-dense object called a neutron star, a city-sized object that packs the mass of the sun in a small space.
Type II supernova sub-categories are classified based on their light curves, which describes how the intensity of the light changes over time. The light of Type II-L supernovae declines steadily after the explosion, while the light of Type II-P supernovae stays steady for a longer period before diminishing. Both types have the signature of hydrogen in their spectra.
20-year-old supernova mystery finally solved
In 2008, scientists caught a Supernova in the act of explodine for the first time. While peering at her computer screen, astronomer Alicia Soderberg expected to see the small glowing smudge of a month-old supernova. But what she and her colleague saw instead was a strange, extremely bright, five-minute burst of X-rays.
With that observation, they became the first astronomers to catch a star in the act of exploding. The new supernova was named SN 2008D. Further study has shown that the supernova had some unusual properties.
“Our observations and modeling show this to be a rather unusual event, to be better understood in terms of an object lying at the boundary between normal supernovae and gamma-ray bursts,” Paolo Mazzali, an Italian astrophysicist at the Padova Observatory and Max-Planck Institute for Astrophysics, told Space.com in a 2008 interview.