Astronomers Are Mapping Out the Opposite End of the Milky Way

Saturday, 04 November 2017 - 11:26AM
Space
Astronomy
Saturday, 04 November 2017 - 11:26AM
Astronomers Are Mapping Out the Opposite End of the Milky Way
NASA/JPL-Caltech
Getting a full view of the Milky Way galaxy has always seemed near impossible, just because we're stuck inside it. It's like trying to draw a map of your city, when you're stuck in a ground floor apartment and can only look out your windows - you can put together an impressive picture with basic measuring techniques, which we have done, but it's not complete.

Which is why a team of astronomers from both the Max Planck Institute for Radio Astronomy in Germany, and the Harvard-Smithsonian Center, have combined some basic measuring techniques with some extremely advanced instruments, to start creating the most complete picture we have yet.

For the first time, they've accurately measured the distance to a "star-forming region" that's 66,000 lightyears away on the far end of the Milky Way, which allows them to start making a much better map of everything in-between. All their research was recently published in a study called "Mapping spiral structure on the far side of the Milky Way." 




The technique they used was a relatively simple one called parallax, something you've perhaps heard of if you're an astronomy buff (or if you're a Green Lantern fan). It's the measuring tactic that involves looking at a single object from two different locations, and measuring how far the object moved to determine its distance. By holding a finger in front of your face, and looking with your left eye and then your right eye, you'll notice your finger is seemingly moving; that's parallax on a tiny scale, and with math, you could use this to measure the distance between your face and your finger.

But parallax is only useful for measuring nearby stars, because with distant stars, the parallax shift becomes so small that it's negligible. The record for measuring distance using parallax was previously 36,000 lightyears, before the current team managed to use the Very Long Baseline Array (VLBA) to measure that star-forming region at 66,000 lightyears away, blowing the previous record out of the water.

It helps that the VLBA is made up of a radio telescope system that spans across North America, Hawaii, and the Caribbean, with ten antennae in different spots - this allows for some much more impressive parallax measurements. Lead researcher Alberto Sanna from the Max Planck Institute explained it this way:

Opening quote
"Using the VLBA, we now can accurately map the whole extent of our Galaxy. Most of the stars and gas in our Galaxy are within this newly-measured distance from the Sun. With the VLBA, we now have the capability to measure enough distances to accurately trace the Galaxy's spiral arms and learn their true shapes."
Closing quote


With all their new data, and with this newest milestone on the far end of the galaxy, obtained using one of the most accurate star-measuring techniques in our arsenal, that team is now putting together a better picture of our enormous neighborhood than ever before. It's still probably spiral-shaped, but soon, we might have a more detailed image of that spiral in our collective heads.

Perhaps Karl Menten of the Max Planck Institute phrased it most succinctly, as they move forward on their mapping project:

Opening quote
"So we have plenty of 'mileposts' to use for our mapping project. But this one is special: Looking all the way through the Milky Way, past its center, way out into the other side."
Closing quote
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