A project of the Dark Energy Survey collaboration


New Beginnings: Our Darkness (Re)Lit

DES0500-6205_cut_MJM.Nebulosity.3.3.960pxWhat clues early in humanity’s search of the sky told the Universe’s story? Emerging from the darkness long ago, what diffuse beacons in the fabric of spacetime offered a glimpse into our place in the cosmos?

When Galileo first pointed his telescope at Jupiter and saw its moons he inevitably would have looked at other parts of the sky. He would have noticed fuzzy patches of light in the sky. Early astronomers could only guess what those fuzzy patches of light were. Collectively, they were referred to as “nebulae”, due to their nebulous forms. Intentional or not, this was the beginning of modern astronomy.

Until the early 1900s, scientists believed the entirety of the universe was contained in what we now call our Milky Way galaxy. They believed that the fuzzy nebulae were much closer to Earth than they actually are. It wasn’t until Edwin Hubble’s observations of Cepheid variable stars in the Andromeda and Triangulum nebulae in the early 1920s that astronomers began to appreciate the size and scope of the universe.

Hubble discovered that those little fuzzy patches of light were entire collections of stars much farther away from us than the rest of the stars in the night sky. In short order, these collections of stars would be referred to as galaxies. That name was natural: the Greeks had already been referring to the fuzzy disc of the Milky Way as a galaxy (the Greeks referred to it as galaxias kyklos which means milky circle; the Latin word galaxias literally means milky way).

Our Milky Way was now one of many, many galaxies.

After changing our notion of what a galaxy is and our place in the universe, Hubble set out to categorize the different kinds of galaxies. Pictured above are many types of galaxies captured by the Dark Energy Camera (DECam). There are at least five or six easy-to-spot galaxies – the edge-on spiral on the right side, the pair of colliding spirals at the bottom center, a big spiral in the top-left, and an elliptical on the far left.

Hubble’s discovery rocked astronomy, and as the fields of astronomy and physics inevitably came together, many new questions emerged. Is the universe static? How did the universe come into being? How old is the universe?

Our current understanding is that the universe is not static.  Nobel prize-worthy research conducted in the late 1990s used exploding stars (supernovae) to reveal that the cosmos is expanding at an increasing rate.  Some new form of energy (dark energy) is overwhelming the force of gravity between all the massive objects in the universe.  The fate of the cosmos is once more brought to light.

So what is driving that expansion? What is causing galaxies to move away from one another, overcoming gravity’s pull?  The answer appears to be dark energy. Very little is known about dark energy, but we believe it makes up about 2/3 of the energy in the universe.

And so we are at the beginning again. Our answers lead us to new questions. There are many more questions to answer, and many more measurements to make.

If you’re interested in seeing these galaxies for yourself, point your telescope toward RA 05:00:34 Dec -62deg 4’.

Written by Det. Marty Murphy [FNAL]
Image by Det. Marty Murphy

13 responses

  1. There is so much more light coming from the darkness than we ever thought possible.

    In the mid 80s, I taught high school physics near Fermilab. Several of us teachers worked with the education office to offer summer institutes for teachers. I was fortunate to meet great people like Lederman, Rocky Kolb, Mike Turner, David Schramm, etc. They inspired me with their information and research.

    One of the projects I worked on was to write some teacher materials for the Cosmic Distance Ladder. It has been a fascinating story. I’ve long since moved and retired from the classroom. But, I still love to teach. I keep a blog on science and astronomy among other things. I did a series of 4 posts on the Cosmic Ladder in my blog. Perhaps you, or readers, would find it interesting. I hope I got the basics correct.

    Thanks for keeping us up to date with this Dark Energy blog.

    April 8, 2014 at 9:47 pm

  2. cay enns

    It’d be nice to mention Henrietta Leavitt.

    April 20, 2014 at 5:00 am

  3. You really make it seem so easy with your presentation but I
    find this matter to be actually something that I think
    I would never understand. It seems too complex and very broad for me.
    I am looking forward for your next post, I will try to get the hang of it!

    July 8, 2014 at 10:02 am

  4. I really like what you guys are usually up too. This sort of clever work and exposure!

    Keep up the wonderful works guys I’ve incorporated you
    guys to my own blogroll.

    July 25, 2014 at 1:20 am

  5. Hello, i believe that i saw you visited my site thus i got here
    to return the desire?.I’m trying to in finding things to improve my site!I suppose its ok to
    use some of your ideas!!

    July 26, 2014 at 9:23 am

  6. Wow un tonne de fantastique infos.

    July 26, 2014 at 10:48 am

  7. Merci mille fois! J’apprécie cette info fort utile!

    July 28, 2014 at 2:06 pm

  8. Vielen Dank! Woplt іch nur mal sagen.

    July 30, 2014 at 8:17 pm

  9. Pretty! This has been an incredibly wonderful
    article. Many thanks for supplying this info.

    August 29, 2014 at 5:23 pm

  10. Today, I went tto the beach ront with my children. I found a sea shell and gave it to my 4 year old daughter and said “You can hear the ocean if you put this to your ear.” Shhe put
    the shell to her ear and screamed. Ther was a
    hermit crab inside and it pinched her ear. She never want to go back!
    LoL I knpw this iss entirely off toplic but I had to tell someone!

    September 2, 2014 at 8:01 am

  11. Este într-adevăr un loc de muncă , nu să fie luate cu grijă .

    September 11, 2014 at 4:28 am

  12. Greetings from Florida! I’m bored at work so I decided to
    browse your website on my iphone during lunch break. I really like the information you provide here and can’t
    wait to take a look when I get home. I’m surprised at
    how quick your blog loaded on my cell phone .. I’m not even using WIFI, just 3G ..
    Anyhow, fantastic site!

    October 23, 2014 at 8:22 am

  13. Pingback: The darkness (re)lit - News

What do you think about the darkness?

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s