Speaking of Galaxies…

In the last post (It’s Full of Galaxies) we saw an infrared image from the Herschel space telescope looking at a tiny piece of the cosmos revealing thousands of galaxies 10 – 12 billion light-years from us.  The image below is also an infrared image, but it is a view of millions of galaxies as taken by the 2MASS (Two Micron All Sky Survey) looking across the night sky.

2MASS View of the Night Sky

      The blue band in the image comes from the stars in our own galaxy.  Note that the distribution of galaxies is not uniform, as one might expect but there are clusters, strings and webs of galaxies.  These structures are remnants of the big bang and the gravitational attraction between matter and the mysterious dark matter.  Think about this:  All of the matter we can see and account for in the Universe only adds up to about 4-5% of the total mass of the Universe!

     The  2MASS survey was conducted using two 1.3 meter telescopes, one in Arizona and the other in Chile, imaging the sky at 3 separate frequencies in the near infrared.  Imagine what this would look like if we were able to use telescopes in space that are above the filtering effects of our atmosphere in the infrared.

      Check these links for more information and a larger image.

Till next time,

RC Davison

It’s Full of…Galaxies!

Image from the Herschel Infrared Telescope courtesiy of the ESA

      These are not stars but galaxies, thousands and thousands of them and each one containing billions of stars.  This snapshot from the Herschel infrared space telescope shows galaxies that are 10-12 billion years old with the red ones being the most distant.  The white  ones indicate galaxies with the greatest star formation.  Looking closely at the image one does not see an even distribution of dots/galaxies, which indicates that some of these galaxies were forming in clusters at that time.

     This image was one taken as part of the Herschel Multi-tiered Extragalactic Survey (HerMES) Key Project.  The purpose of the project is to study the evolution of galaxies in the distant cosmos.  This particular image lies in a region of space called the Lockman Hole, which is in the constellation of Ursa Major and provides a relatively unobstructed view into a far corner of the Universe.

     The next night you are out, take a look up into the night sky and think about the fact that all you can see is in the optical region of the spectrum.  Consider what lies beyond our narrow view of the vast cosmos.

Till next time,

RC Davison

Our Closest Galaxy

Pop quiz!  What’s the closest galaxy to our Milky Way?

Nope! It’s not Andromeda.  And, it is not the Large or the Small Magellanic Clouds. (Which all those who live in the Southern Hemisphere get to see!)

The closest galaxy to ours is the irregular dwarf galaxy Canis Major, which is about 42,000 light-years from the center of the Milky Way.  The galaxy was only discovered in 2003, as it is obscured by dust and gas that lays within the Milky Way.  Andromeda (M31) is about 2.5 million light years away from us, which makes it the 35th most distant galaxy from the Milky Way.  Andromeda is the closest spiral galaxy to the Milky Way.

The Andromeda galaxy has the distinction of the being the largest galaxy in our gravitationally bound local group of about 40 galaxies.  It’s about twice as big as Milky Way, and that places our galaxy as the second largest in the group, followed by Triangulum (M33), a beautiful spiral galaxy that is possibly a satellite galaxy of Andromeda.

Andromeda Galaxy - Image by Tony Hallas http://astrophoto.com/contact.htm Triangulum Galaxy - Image by Manfred Konrad http://www.astrofotografie-laupheim.de/

Till next time,

RC Davison

Inside The Milky Way

Inside The Milky Way” is a new production by the National Geographic Channel that aired Sunday night and will be broadcast again on Thursday, October 28th at 9 pm.  I saw most of the program and highly recommend it.

Stunning visuals, animations, and the latest hot topics in astronomy are intelligently discussed in this 2-hour program.  Black holes, dark matter, galactic superclusters, and the Andromeda/Milky Way collision (In about 2 billion years – don’t sweat it!) are some of the topics covered.  (Just ignore the sound effects for the supernova!)

Check out the web site for some videos and photos.  Enjoy!

Till next time,

RC Davison

It’s Full of Stars!

Initially, I was just going to put up a link to the European Southern Observatory’s list of top 100 images, which has enough pictures to keep any fan of the cosmos happy.  But, I made the mistake of checking out NASA’s Hubble site, which has a huge collection of images, and I compounded that mistake by looking at the European Space Agency’s (ESA) site for Hubble.  Wow!  I think I’ve overloaded my neural-net!

There is just way too much to look at on these sites!  As a tantalizing tidbit, take a look at this beautiful Hubble image of the spiral galaxy NGC 5866 seen edge on.

Spiral Galaxy NGC 5866 Seen Edge On - Hubble Image

Click on the link above for larger images (down-loadable) where you can enjoy the exquisite detail Hubble captured of this galaxy.

One last thing.  ESO is running a contest – ESO’s Hidden Treasures for anyone that has an interest in creating a new image from their data archives.  They provide instructions on what you have to do to create the image, but hurry, the contest ends on November 30, 2010.

Till next time,

RC Davison

The Beautiful Barred Spiral Galaxy – NGC 1365

If you’ve got a few minutes check out the European Space Observatory site and specifically this link, which shows the difference between what we see in the visual part of the spectrum, versus the infrared part of the spectrum in a 38 second movie.

Barred Spiral Galaxy NGC 1365 - Image courtesy of ESO

There is great interest in the barred spiral galaxies because it is believed that our Milky Way is also a barred spiral.  NGC 1365 is about 200,000 light years across, which makes it about twice as big as our home galaxy.  This galaxy is about 60 million light years from us and is part of the Fornax galaxy cluster.

If you’ve got a few minutes, check out the site.  As you’re gazing at this incredible island of stars, think about how many planets may orbit the 400 billion or so stars in this galaxy, and of those, how many may have life looking back at us in equal awe and wonder…

Till next time,

RC Davison