Thursday, August 09, 2012

3-D Tour of the Universe: Like a BOSS

The astrophysicists behind the Baryon Oscillation Spectroscopic Survey (BOSS) have an ambitious goal: Pinpoint roughly 1.5 million galaxies from the past 6 billion years and over one hundred thousand quasars stretching back to the universe's infancy 12 billion years ago.

They're about one third of the way there. With the latest data released yesterday, the team has composed a 3-d map of hundreds of thousands of galaxies and stars surveyed thus far. Additionally, the researchers have unveiled a teaser video, seen below, that allows you to drift through a cosmic sea.

Aside from providing a breathtaking view of our cosmic surroundings, BOSS scientists are discovering more about the dark energy and matter that comprise 96 percent of our universe. Additionally, the survey should reveal more details about our universe's expansion.

Mapping this huge chunk of the universe, while aesthetically pleasing, was motivated by scientific necessity. Artifacts from the early universe have left detectable fluctuations covering vast distances across the cosmic landscape. These fluctuations are only detectable on the scale of hundreds of millions of light years, so BOSS acts as an over-sized measuring tool used to uncover facts about our universe's origins.

In this video, scientists take us on a tour through data from an earlier sky survey that tracks galaxies up to 1.3 billion years old. The latest data refined the locations of the objects in the video, helping scientists map galaxies, stars and quasars in three dimensions.

This video not only looks amazing but also blows my mind upon further reflection. We're looking at galaxies and stars dating back billions of years (this video has galaxies going back to a little over 1 billion years). Although the video looks like a tour through a "snapshot" of the universe, you're actually seeing its evolution while everything seems to stand still.

Some of the galaxies in the map may be from one billion years ago, while objects closer to our backyard are much more recent. This reflects the inherent limits and benefits of looking deep into the cosmos: We can probe the universe's infancy, but we can't see what distant locations look like presently. There's an intimate relationship between distance and age at play when we gaze into the night sky.

For the BOSS experiment, scientists are trying to narrow down the distances -- and consequent age -- of our universe's largest objects. To do this, researchers analyze acoustic fluctuations stemming from a battle in the early universe between gravity and gas pressure. These fluctuations leave their mark throughout the evolution of the universe, allowing scientists to more accurately study its history.

The fluctuations are only measurable across nearly incomprehensible distances, however. In fact, the fluctuations don't reveal themselves until scientists can map distances in the range of 100 megaparsecs, or roughly 325 million light years. For comparison, our Milky Way galaxy is about 100,000 light years across, and the whole observable universe spans about 45 billion light years.

You can look through the latest (2-D) galaxy map online, and there are even tools for educators to incorporate the data in their classroom.

BOSS forms only part of the Sloan Digital Sky Survey III, a huge scientific project that uses data from the Sloan Foundation Telescope in New Mexico, but BOSS scientists will be mapping the sky until 2014 after collecting data for six years. For now, we have a healthy chunk of the night sky to keep us mesmerized.


If you want to keep up with Hyperspace, AKA Brian, you can follow him on Twitter.

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