04Jul
By: Astroathens On: July 4, 2017 In: Astronomy Comments: 0
  • Starburst Galaxy Messier 94
  • What is a starburst galaxy?
  • There are areas in our universe where star formation comes in very high concentrations and very quickly. Where literally BILLIONS of stars are forming at once. This is due to the conditions of that particular area in space. IN this case we are looking at a galaxy.
  • What does it take for billions stars to form at once?
  • Regions where theres A LOT of dust. Why ? Because SPACE DUST contains the necessary elements for stars to be born. And when these elements come together under hot conditions can accumulate and form stars.
  • Where is this galaxy located?
  • Messier 94 is 15 million light-years away, found in the northern constellation of the hunting dogs, Canes Venatici.
  • How big is it?
  • 30,000 light-years across, with spiral arms. However this Hubble space telescope image is of only the central region that spans only 7,000 light years across.
  • Why is it so blue? And what are the pinkish areas?
  • That blue sparkly ring is all very massive, young and hot BLUE STARS!! Young— aka less than 10 million years old! This means since they’re so young they all formed so recently and so RAPIDLY in this galaxy. RAPID STAR FORMATION = STARBURST GALAXY.
  • In the cosmic world age is totally different that it into us. To these stars, our 100 years of a single human life is a blink of an eye to them (that is if stars had eyes!)
  • And to stars like our Sun (yellow M stars) that will live around say 500 million years, these blue stars are total babies.
  • The TOP left region of stars that appear a bit pinkish are older red stars. Red stars like red giants usually have been around for 300-500 million years—and actually form through the death of a star like our Sun. When our sun begins to die it will EXPAND and begin to COOL down a lot. As it begins to expand and cool it becomes more red. IN SPACE RED IS COOLER, BLUE IS HOTTER——oh the irony of bathroom sinks that use blue to indicate cold and red for hot.
  • What are the darker regions?
  • THERE IS A LOT OF DUST HERE.  Both the lighter foggy looking spots and the darker shadow spots are all dust!
  • So why are some dark and some bright?
  • This is reflection vs absorption.
  • Like with Nebulae, based on the type of elements present in the dust AND where the stars are located around the dust is what determines its opacity.
  • SO— if there are a lot of stars located behind the dust like if you want to take a photo of someone but they’re standing in front of a bright light facing you an the light is behind them they come out like a silhouette.
  • However turn them around and make the light face their face, the light reflects off of them so you an capture a photo.
  • Space works the same in this case. So since stars give off light if there are more located in front of the dust clouds, then they reflect the light and appear bright from our angle as we captured the photo!
  • This images focuses on the galaxy’s nucleus (aka center) and the dust lanes are near the center and spreads all the way out through the ams of the galaxy if we had a full scale image.
  • Why is it spiraling towards the center like a toilet when flushing?
  • ITS THE BLACK HOLE
  • Why does the toilet spiral down when you flush it? First you have forces acting on the water. You have gravity pulling it down when you release the drain during the act of flushing. Next you have a tunnel-like thing aka the pipe that the water drains down.
  • Black holes have the force, a HUGE force… GRAVITY. Also it is tunnel-like. It is a circular opening and when stuff gets close enough WOOSH the black hole pulls it in by it’s gravity and down they go (or in the case of spacetime- they go THROUGH because what we understand right now is the fabric of space is linear, a plane so is there really a DOWN?)
  • Do we know why this galaxy compared with others have such rapid car formation?
  • As a result, while the small, bright nucleus is typical of the Seyfert class of active galaxies, M94 is also known as a starburst galaxy. Because M94 is relatively nearby, astronomers can explore in detail reasons for the galaxy’s burst of star formation.
  • Image Credit: ESA/Hubble and NASA

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