Category Kids Queries

Actually, we don’t know for sure – no more than a bacteria deep inside your belly knows your hair color or shoe size. But unlike bacteria, human astronomers have high-tech sensors and space telescopes. We can measure the distances and densities of star clusters and peer through dense nebulae to the galaxy’s core. By comparing these findings with images of distant galaxies, we get a good idea of our home galaxy’s structure.

Several different telescopes, both on the ground and in space, have taken images of the disk of the Milky Way by taking a series of pictures in different directions – a bit like taking a panoramic picture with your camera or phone. The concentration of stars in a band adds to the evidence that the Milky Way is a spiral galaxy. If we lived in an elliptical galaxy, we would see the stars of our galaxy spread out all around the sky, not in a single band.

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A little bit of sun goes a long way. Sunlight contains invisible ultraviolet (UV) rays that can damage your skin, causing it to burn or wrinkle, and even lead to skin cancers. A colored chemical material in our skin called melanin absorbs UV rays to minimize the damage. Fair-skinned people (whose ancestors come from less sunny places) have less melanin, so they’re more susceptible to sunburn and forming harmless spots of melanin known as freckles. People with darker skin (whose ancestors come from sunny places) produce more melanin to combat UV damage. But even high levels of melanin aren’t enough to protect skin from wrinkles caused by overexposure to the sun.

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A sunny day can do more than just raise your spirits – it can make you healthier! Your body converts sunlight into vitamin D, a vital vitamin for stronger bones. Adults who get sunlight early in the day are likely to have a lower body mass index, a measure that takes into account weight and height, according to recent study.

The fact that people sleep better if they get light in the morning could account for this, since people who get enough sleep have an easier time managing their weight. The so-called “sunshine vitamin” helps the body absorb calcium, which is essential for bone health.

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It’s a big ball of gas accounting for 99.8 percent of the total mass of the solar system. More than a million Earths would fit inside the sun! A process called nuclear fusion converts hydrogen to helium deep in the sun’s core, where temperatures hit a balmy 27 million degree Fahrenheit (15 million degrees Celsius). Fusion creates energy that travels to the sun’s surface in a journey that can take 100,000 years.

The sun produces a wide range of light wavelengths called a spectrum. In addition to the familiar colors people see, the sun’s spectrum contains X-rays, ultraviolet and infrared light and radio waves. The Earth’s atmosphere fortunately blocks most of the harmful wavelengths; without this shielding effect, life would not be possible.

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Think Earth is the most important spot in the solar system? The sun is the real star of the show – literally! The closest star to Earth, it’s the source of all our heat and light. Life wouldn’t exist without it. It’s also the center of our solar system and by far its largest object. Our star’s enormous gravitational pull grips the planets, dwarf planets, asteroids, and comets, keeping them from spinning into deep space. Put simply, we wouldn’t have a solar system without the sun.

Scientists estimate the sun has at least another 5 billion years before it turns into a red giant and swallows up Mercury and Venus. It will also destroy all life on Earth because it will be close to the planet once that change occurs. The temperature of the sun will also increase tenfold from 18 million to 180 million degrees Fahrenheit. The increase in the sun’s size when it finally begins to change will be due to the heat increase causing expansion.

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That would be Andromeda, a spiral galaxy like the Milky Way. Astronomers believe it contains as many as a trillion stars. At 2.5 million light-years away, Andromeda is the farthest thing we can see with the naked eye, but it’s getting closer all the time. Someday, the Milky Way and Andromeda galaxies will collide, sharing their star dust and spawning new stars. It’s doubtful any humans will see this cosmic collision, which won’t happen until four billion years in the future.

Picture Credit : Google