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Hubblecast 02: Galaxy bars and supermassive black holes

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Hubble has delivered an unrivalled snapshot of nearby barred spiral galaxy NGC 1672. This remarkable image provides a high-definition view of the galaxy’s large bar, its fields of star-forming clouds and its dark bands of interstellar dust. This is the Hubblecast! News and Images from the NASA/ESA Hubble Space Telescope. Travelling through time and space with our host Doctor J a.k.a. Dr Joe Liske. Welcome to the Hubblecast! Now when we look around us in the Universe with powerful telescopes, essentially all the light we see comes to us from billions and billions of stars. And these stars are gathered together in galaxies. So, galaxies are essentially just huge collections of stars, gas and dust, and they come in an enormous variety of different shapes and sizes. Now, today I’d like to talk to you about one particular galaxy and that's NGC 1672 located in the Dorado or Swordfish constellation. Now here is a spectacular brand new image from the NASA/ESA Hubble Space Telescope As you can see straight away it is a spiral galaxy. In fact it is a prototypical example of a so-called barred spiral galaxy and it is viewed nearly faced on. Barred spirals differ from normal spiral galaxies, in that their arms do not twist all the way into the centre. Instead, they are attached at two ends of a straight bar of stars. Four principal arms extend from the centre and give NGC 1672 a rather symmetric appearance. Eye-catching dust lanes extend away from the nucleus and follow the inner sides of the spiral arms. Hot, young blue stars are seen in vigorous star forming clusters in the galaxy’s spiral arms. Delicate curtains of dust partially obscure the light of the stars behind them and colour them red. NGC 1672 is almost like a sister galaxy to our own galactic home, the Milky Way. The Milky Way also has a huge bar of stars, which was recently seen in great detail by the infrared eyes of the NASA Spitzer Space Telescope. The two galaxies also have in common that their spiral arms are quite loosely wrapped. Now, astronomers believe that barred spiral galaxies have a unique mechanism that channels gas from the disk inwards towards the centre of the galaxy. And it is thought that this gas also makes a really good meal for a putative supermassive black hole that sits at the centre. Moreover, bars are thought to be quite short-lived. So, the big question is: will non-barred spiral galaxies develop the bar in the future, or have they hosted a bar in the past that has since died out? Behind the galaxy several more distant galaxies are seen. They are coloured caramel by the dust in NGC 1672. Also seen in the image are a few bright, much closer, foreground stars from our own Milky Way. Astronomers are still puzzled about how bars actually form. They could be the result of instabilities in the disk that harbours the spiral arms, or they could develop in the aftermath of galactic collisions. In any case, the formation and evolution of bars is still a matter of debate. This is Dr J signing off for the Hubblecast. Once again nature has surprised us beyond our wildest imagination … Hubblecast is produced by ESA/Hubble at the European Southern Observatory in Germany. The Hubble mission is a project of international cooperation between NASA and the European Space Agency.

Video Details

Duration: 4 minutes and 23 seconds
Country: Germany
Language: English
Producer: Lars Lindberg Christensen
Director: Lars Lindberg Christensen
Views: 154
Posted by: esahubble on Feb 25, 2010

Hubble has delivered an unrivalled snapshot of the nearby barred spiral galaxy NGC 1672. This remarkable image provides a high-definition view of the galaxy's large bar, its fields of star-forming clouds and its dark bands of interstellar dust.

More information at credits at: http://www.spacetelescope.org/videos/html/heic0706a.html

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