What are the 4 main parts of a spiral galaxy?
A galaxy contains stars, gas and dust. In a spiral galaxy like the Milky Way, the stars, gas, and dust are organized into a “bulge,” a “disk” containing “spiral arms,” and a “halo.” Elliptical galaxies have a bulge-like central region and a halo, but do not have a disk.
What is the difference between a spiral galaxy and a barred spiral galaxy?
The bulge and halo consist mainly of older stars, where spiral arms have more gas, dust and younger stars. Our Milky Way Galaxy is a spiral galaxy. Some spiral galaxies are what we call “barred spirals” because the central bulge looks elongated ” like a bar. The stars in ellipticals tend to be older.
Why does the bulge of a spiral galaxy appear yellowish in Colour?
The central bulge or bar is yellow indicating older stars, while the bright nebulae and young blue stars formed from gas and dust in the galaxy trace out the spiral arms within the disk. These differences can be traced back to the relative amounts of gas and dust contained within the galaxies.
What is the youngest type of galaxy?
Called I Zwicky 18, it may be as young as 500 million years old (so recent an epoch that complex life had already begun to appear on Earth). Our Milky Way galaxy by contrast is over 20 times older, or about 12 billion years old, the typical age of galaxies across the universe.
Which type of galaxy is the largest?
Why is the galaxy spiral?
Astronomers believe that galaxies have spiral arms because galaxies rotate ” or spin around a central axis ” and because of something called “density waves.” A spiral galaxy’s rotation, or spin, bends the waves into spirals. Stars pass through the wave as they orbit the galaxy center.
Does the Milky Way have spiral arms?
Our Solar System resides roughly 26,000 light-years away from the Galactic Center. Our Milky Way galaxy has spiral arms, where stars are born from clouds of molecular gas and shine for billions of years. Astronomers think the Milky Way has 4 main spiral arms and a number of fragments of arms, called spurs.
What is the average separation between spiral arms?
We show for a typical arm cross-cut, a separation of 400 pc between the mid-arm and the dust lane (at the inner edge of the arm, toward the Galactic center).
What are the 2 types of spiral galaxies?
Spiral galaxies They are divided into two parallel classes: normal spirals and barred spirals. The normal spirals have arms that emanate from the nucleus, while barred spirals have a bright linear feature called a bar that straddles the nucleus, with the arms unwinding from the ends of the bar.
What is biggest galaxy or universe?
The Biggest of the Big Located almost a billion light-years away, IC 1101 is the single largest galaxy that has ever been found in the observable universe.
What is the oldest star in the galaxy?
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