Category Archives: astronomy news

Celebrating 19 Years of Hubble Space Telescope

Wow!!!

Arp 194 -- two colliding galaxies, a streamer of star birth and a background galaxy -- all shown by HST.  (Click to embiggen.)
Arp 194 -- two colliding galaxies, a streamer of star birth and a background galaxy -- all shown by HST. (Click to embiggen.)

HST is probably the undisputed champion imager of colliding galaxies. For 19 years it’s been showing us the view as distant things go “bump” in the night. So, it’s only natural that the folks at Space Telescope Science Institute and the European Hubble office would celebrate the telescope’s 19th year on orbit with a smashing image of galaxy collision.  This one’s a doozy, folks!

This image actually shows a trio of galaxies, only two of which are doing the actual interacting.  The trio is called Arp 194, At first glance, it looks like one of them has sprung a leak. The bright blue streamer is really a stretched spiral arm full of newborn blue stars.  You see these a lot during the aftermath of galaxy collisions and this is easily one of the most impressive ‘star fountain’ formations I’ve ever seen.

The two nuclei of the colliding galaxies can be seen in the process of merging at the upper left — they look like a pair of owl eyes. The blue bridge looks like it connects to a third galaxy. In reality the galaxy is in the background and not connected at all — although astronomers aren’t sure yet if there is any interaction between it and the northern pair of galaxies (which are interacting). Hubble’s sharp view allows astronomers to try and visually sort out what are foreground and background objects when galaxies, superficially, appear to overlap.

This whole scene is playing out about 600 million light-years from us, in the direction of the constellation Cepheus. The region has a number of interesting galaxy interactions, so this little galactic birthday party will likely not be the last that HST sees.

I must say, this is a great birthday card for HST. The telescope’s accomplishments are many: during the past 19 years Hubble has made more than 880,000 observations and snapped over 570,000 images of 29,000 celestial objects.

Into the Starry Deeps

Where Stars Get Started

NGC 6520 and Barnard 86 set against the backdrop of the Milky Way. Courtesy NOAO. (Click to embiggen.)
NGC 6520 and Barnard 86 set against the backdrop of the Milky Way. T.A. Rector, University of Alaska, Anchorage and NOAO/AURA/NSF. (Click to embiggen.)

Let’s get back to talking about astronomy.  During the recent “Around the World in 80 Telescopes” event for IYA, the National Optical Astronomy Observatory released this stunning image of the open star cluster NGC 6520 and the dust cloud Barnard 86.  The wash of stars in the background is the Milky Way in the direction of the constellation Sagittarius.

I like this picture because it shows two steps of star formation. The first is in that dark cloud named Barnard 86. It’s a Bok globule, one of those dusty, dark places that coalesce together to form stars. So, there could be stars forming inside that dust cloud.

See that little cloud of glittering stars right above Barnard 86?  Those are bright young newborns that probably formed out of some part of Barnard 86. They’re the second step of star formation — the finished product. They look bluish, which is one clue that they’re young. And they really stand out against the reddish older stars in the Milky Way in that region. Go ahead and embiggen that image — it’s worth taking the time to explore!