The article was published at The Conversation.
The Centre for Astrophysics and Supercomputing is at the Swinburne University of Technology.
My favorite thing about my job as an astronomer is the rare moments when I get to see beautiful distant galaxies, whose light left them millions to billions of years ago. It's a combination of pure awe and scientific curiosity that makes me excited about "Galaxy hunting."
In astronomy today, we handle enormous amounts of data by writing and running programs to work with images of the sky. We don't always have the experience of looking at every square inch of the universe while we study it. I'm going to show you how I get my fix of wonder by looking at the stars that only a few people will ever have seen.
There are over 2 trillion galaxies in our observable universe.
There are 15 weird galaxies in our universe.
Galaxies are at your fingertips.
Astronomers used to tediously examine photographic plates after a long, cold and lonely night of observing. In the 21st century, we have access to information on the internet.
Automatic telescopes and surveys give us a lot of data that we need machines to analyze. Humans will only look at what the computers have deemed interesting in some cases. Massive amounts of data are hosted online and waiting to be admired.
You can get a universe atlas online.
One of the best online tools to look at our universe is Aladin lite. We can look at the entire sky for hidden galaxies and even learn about their populations and evolution.
The Cartwheel galaxy is one of the most visually stunning galaxies out there. You can search for both the popular name of an object and known coordinates in the Aladin interface. The location will be in the interface.
The online view of the Cartwheel galaxy is 500 million light-years away from Earth. The image is from the sky survey by the NASA and theSTScI.
The first image we see is from the sky survey. The colors we see are from the telescope. These are representative of what the universe would look like.
A general rule of thumb as an astronomer is that the color of the galaxies is due to the environment they are in. It is important to note that blue and red are both hotter than red.
The outer ring of the galaxy appears to be more blue than the center red section. This might show star formation in the outer ring, but not in the center.
To confirm our suspicions of star formation, we can look at data from different surveys. Young stars emit a lot of UV radiation. We are now looking at only UV wavelength, and what a difference that makes!
The basics of star names and stellar evolution.
The online view of the Cartwheel galaxy is in the GALEX UV wavelength. The material on this site was created, authored and/or prepared for NASA under contract NA55-26555, unless otherwise specifically stated, no claim to copyright is being asserted by STScI.
The center of the universe seems to disappear from our image. The section is likely home to older stars with less active stellar nurseries.
There are 20 different surveys in Aladin. They give an image of the sky from a variety of sources.
When I am wandering the universe looking for interesting galaxies, I usually start out in optical and find ones that look interesting to me. I use the different surveys to see how the images change when looking at specific wavelengths.
'Where's Waldo' is a universal thing.
Let the game begin after you've had a crash course. You can spend hours looking at the amazing images. I recommend looking at the images from DECalS/DR3 for the highest resolution and detail.
Drag the sky atlas around. If you find something interesting, you can find out more about it by clicking on the target icon and selecting the object.
Here are my favorite finds of the different types of objects you might see.
A spiral galaxies has a central rotating disc with large spiral "arms" curving out from the denser central regions. They are gorgeous. Our own spiral galaxy is called the Milky Way.
Stars occupy almost a 3D ellipse at times in elliptical galaxies, which are largely featureless and less "flat" than spirals. Older stars and less active star-forming regions are found in these types of galaxies.
Lenticular galaxies are flat and featureless in the night sky. The "in-between" of spiral and elliptical galaxies can be thought of as these. The majority of star formation has stopped, but lenticular galaxies can still have significant amounts of dust.
There are other types of galaxies, including mergers and lenses, which are waiting for you to find them. I would love to see what you find on the social network.
The Conversation's article is a Creative Commons licensed one. The original article can be found here.
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