THE UNIVERSE
The universe is the hole of existence—all of space, matter, energy, and time. The universe is so watched as to be unimaginable, but we do know that it is expanding following its beginning 13.8 billion years ago in an explosive event called the Big Bang.
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UNDERSTANDING THE UNIVERSE
People used to think of this thing as a giant sphere, but we now know that things are not so simple. The universe probably has no center or outer edge; only a fraction of it is visible to us. The observable universe may be vastly bigger than this, perhaps infinitely so. A dense universe would bend itself into a closed shape. Traveling in a straight line would bring you back to your starting point.
Read also: A VIEW OF THE WORLD
The shape of space
The three dimensions of space are bent by the force of gravity from matter in the universe into a fourth dimension that we cannot see. This is hard to visualize, so scientist use the metaphor of a two-dimensional rubber sheet to explain the idea. The mass of this thing could twist this elastic sheet in one of three ways, contingent upon how thickly loaded with issues the universe is.
Most scientists now think the shape of this thing is flat. If the universe is not dense enough, it might stretch into an open shape, making it infinite in size with no outer edge. Just the right amount of matter will give the universe a flat shape. This would also be infinite in size, with no outer edge.
The scale of space
The universe is tremendous to such an extent that we can’t see the value in its size without taking leaps of scale. In this series of pictures, each stage represents a microscopic speck of the image to its right. When dealing with the vast distances in space, kilometres are not big enough. Instead, astronomer use the speed of light as a yardstick. Light is so quick, it can go around Earth 7.5 times in a moment. One light year is the distance light travels in a year—nearly 10 trillion km or 6 trillion miles.
EARTH AND MOON
Earth is 12,756 km or 7,926 miles wide. Our nearest neighbour in space is the Moon, which orbits Earth at a distance of 384,400 km, or 238,855 miles. If the Earth were the size of a football, the moon would be the size of a melon, about 21 m or 69 ft. away.
SOLAR SYSTEM
The sun family of 8 planets occupy a region of 9 billion km, or 5.6 billion miles wide. If earth were a football, it would take 5 days to walk across this part of the solar system, and the nearest star would be a 58-year walk away.
STELLAR NEIGHBOURHOOD
The nearest star to the sun is Proxima Centauri, which is just 4 over 4 light years away. There are around 2000 stars within 50 light years of the sun; these make up our stellar neighborhood, which is a tiny fraction of the Milky Way galaxy.
MILKY WAY GALAXY
The Milky Way galaxy is a vast cloud of 200 billion stars. Its shape resembles a pair of pride eggs held back-to-back with a central bulge surrounded by a flat disk. It measures 1 lakh light years across the disc and 2000 light years deep through the bulge.
LOCAL GROUP OF GALAXIES
The Milky Way is just one of perhaps 7 trillion galaxies in the observable universe that exist in groups called clusters. Together, by gravity, the Smooth Way is important for a bunch known as the neighborhood bunch, which is around 10 million light years wide.
SUPERCLUSTER
Clusters of the Galaxy exist in an even larger grouping called super clusters. We live in the Virgo super cluster, which is one of millions of super clusters in the non-universe. Between these are immense empty areas called cosmic voids.
UNIVERSE
Superclusters are thought to form a vast web of filament riddled with enormous voids containing no galaxy. The true size of the universe is a mystery, and only a fraction of it is visible to us. This thing may even be infinite in size.
