Skip to main content
Labels
Off On

Dark Matter: Supernova Refsdal

Untangling repeated imagery Full Story Below

Small blobs of light across frame Small blobs of light across frame
A box enlarges small area with four circles, same supernova A box enlarges small area with four circles, same supernova
Expanded field of view shows another location for supernova
New dot of light appears at top left New dot of light appears at top left
Color map shows concentration of dark matter, more at center Color map shows concentration of dark matter, more at center
Loading images...

A 2012 image reveals a galaxy cluster is creating multiple, magnified images of a distant galaxy. Is dark matter the culprit?

While studying this galaxy cluster again in November 2014, researchers captured four images of the same supernova in that galaxy.

Researchers predicted the supernova would appear again elsewhere, but their observations in October 2015 revealed nothing.

In December 2015, they looked again—and caught the supernova’s reappearance, proving some predictions were accurate.

Researchers used dark matter models to correctly predict the supernova’s reappearance, refining our understanding of its distribution.

Galaxy Cluster
Supernova Discovery
First Follow-up
Supernova’s Reappearance
The Outcome

Dark Matter: Supernova Refsdal

Predicting the reappearance of a supernova’s light.

Scientists know more about what dark matter isn’t than what it is. Though dark matter has not been detected with telescopes, we know it exists because of its gravitational effects on objects we do see—objects that emit or reflect light. When space is warped by dark matter’s gravity, the light of distant galaxies—and bright objects within them, like supernovas—appear distorted. Using this and other methods, astronomers calculate that there is much more dark matter in the universe than matter we can currently see.

Supernova Refsdal exploded in a galaxy over 9 billion light-years away. In between this supernova and Earth is a galaxy cluster. Like all galaxy clusters, it contains abundant amounts of dark matter. The mass of the dark matter in the galaxy cluster used gravity to distort light from the supernova, causing the supernova’s light to travel to Earth along multiple paths. This effect, known as gravitational lensing, also created multiple images of the background galaxy where the supernova exploded. Some of the paths the supernova’s light took were longer than others and took more time to travel. The case of Supernova Refsdal offered researchers the opportunity to predict when light that took a longer path—but hadn’t yet arrived at Earth—would reappear.

Scientists constructed models and made predictions about when and where the supernova’s light would reappear. (Their models varied based on their hypotheses about the dark matter’s distribution.) Researchers’ first follow-up observations showed nothing. Later observations proved a few models correctly predicted where the supernova’s light would reappear. This timely science case allowed astronomers to further refine the amount and distribution of dark matter in their models of this and other galaxy clusters.

Quick Facts: Supernova Refsdal

Also known as: SN HFF14Ref in the MACS J1149.5+2223 galaxy cluster

Distance from Earth: 9.3 billion light-years (supernova); 5 billion light-years (galaxy cluster)

Type of object: Supernova

Location in the sky: Leo Constellation

Did you know: The first observation of the supernova, which appeared four times, is known as an Einstein Cross.

Explore More About Dark Matter

Find out more with these additional resources from NASA’s Universe of Learning

ViewSpace Videos
Watch videos that examine dark matter
Chandra Field Guide
Learn the basics behind dark matter
AstroPix
Explore images that show the location of dark matter
NASA’s Universe of Learning
Examine the Bullet Cluster with a printable handout

Credits: Supernova Refsdal

2012 image of MACS J1149.5+2223 from the Hubble Space Telescope: NASA, ESA, W. Zheng (JHU), M. Postman (STScI), and the CLASH Team

March 2015 image of MACS J1149.5+2223 from the Hubble Space Telescope: NASA, ESA, and S. Rodney (JHU) and the FrontierSN team; T. Treu (UCLA), P. Kelly (UC Berkeley), and the GLASS team; J. Lotz (STScI) and the Frontier Fields team; M. Postman (STScI) and the CLASH team; and Z. Levay (STScI)

October 2015 and December 2015 images of MACS J1149.5+2223 from the Hubble Space Telescope: NASA, ESA, and P. Kelly (University of California, Berkeley); NASA, ESA, and S. Rodney (University of South Carolina) and the FrontierSN team; T. Treu (UCLA), P. Kelly (UC Berkeley) and the GLASS team; J. Lotz (STScI) and the Frontier Fields team; M. Postman (STScI) and the CLASH team; and Z. Levay (STScI)

Dark matter map based on A. Zitrin 2020, arXiv e-prints, arXiv:2008.10642 (Figure 2)

Content development by Claire Blome, Dr. Kelly Lepo, Holly Ryer

Design by Elizabeth Wheatley

Web development by Isaar Sadr, Lara Wilkinson

Subject-matter expertise provided by Dr. Patrick Kelly