This site may earn affiliate commissions from the links on this page. Terms of utilize.

Universe map

Hundreds of scientists from the Sloan Digital Heaven Survey (SDSS-Three) collaboration worked together to produce this largest-ever, extremely shiny, three-dimensional map of the sky. And it'southward non even the whole sky. Performed as office of the Baryon Oscillation Spectroscopic Survey (Boss) program of SDSS-Three, the prototype above represents a just a unmarried piece: iii% of the volume they mapped. Each point of color stands for an entire galaxy. The colour of each galaxy gives its altitude from Earth, ranging from yellow on the near side of the slice to purple on the far side. The grey places are gaps in the information. And, of course, whatever map like this is also looking back in time, showing united states what was happening when the calorie-free nosotros see was emitted upwards to billions of years in the by.

In the image below, the rectangle on the far left shows a cutout of 1000 square degrees in the sky containing nearly 120,000 galaxies, or roughly 10% of the total survey. The spectroscopic measurements of each galaxy — every dot in that cutout — transform the two-dimensional moving-picture show into a iii-dimensional map, extending our view out to vii billion years in the past. The brighter regions in this map correspond to the regions of the Universe with more than galaxies and therefore more dark matter. The extra matter in those regions creates an excess gravitational pull, which makes the map a test of Einstein's theory of gravity.

In total, the map encompasses a book of some 650 billion cubic calorie-free years. It shows that galaxies are organized in abaft superclusters shot through the void, a superstructure of baffling scale that came into being as matter was flung out into the cosmos in the outset fraction of a second after the Big Bang. SDSS elaborates:

BOSS measures the expansion rate of the Universe by determining the size of the baryon audio-visual oscillations (BAO) in the three-dimensional distribution of galaxies. The original BAO size is adamant by pressure waves that traveled through the immature Universe up to when information technology was only 400,000 years old (the Universe is soon 13.8 billion years old), at which point they became frozen in the matter distribution of the Universe. The cease result is that galaxies are preferentially separated by a characteristic distance, that astronomers call the audio-visual scale. The size of the audio-visual scale at 13.48 billion years ago has been exquisitely determined from observations of the cosmic microwave background from the low-cal emitted when the pressure waves became frozen.

SDSS added that measuring the distribution of galaxies since that time lets astronomers measure how dark affair and nighttime energy have competed to govern the rate of expansion of the universe.

Building the volumetric map naturally involved a lot of associated observations and insights, the sum of which produced several associated reports that the BOSS squad submitted this week to the Monthly Notices of the Royal Astronomical Society. The reports deal with ideas similar the way that the abaft clusters of galaxies inform united states of america well-nigh how the universe is changing through time.

The astronomers also use their observations to zero in farther on the nature of nighttime matter and dark energy. They calculated the amount of thing and dark energy that make up the present-day universe — and the net impact of all that night matter and energy on the present state of the cosmos, over a menstruum of billions of years. "Measuring the audio-visual scale beyond cosmic history gives a directly ruler with which to measure the Universe'south expansion rate," said collaborator Dr. Ariel Sanchez. Dr. Florian Beutler, another collaborator, said, "If night energy has been driving the expansion of the Universe over that time, our maps tells us that information technology is evolving very slowly, if at all. The change is at most 20 per cent over the past seven billion years."

For further, more scientifically toothsome reading, including PDF versions of the reports related to this cosmic map, check out what the Max Planck Institute for Extraterrestrial Physics had to say about the project.

Or read from ExtremeTech: What is dark matter? and What is dark energy?