Featured image is from NASA. See below for explanation and credits.
It was a bit of a chaotic show in the studio. Just before start, we were told that our show would be interrupted a half hour in by basketball. Plans were thrown out and the drawing board went up. Blessedly, the sports only hijacked our live-stream. The day turned in to a beautiful show of music, with a great discussion on dark matter just before the end (around 1.5 hours in). The planned airing of an interview on exoplanets with astronomer and TED fellow Lucianne Walkowicz has been postponed.
The featured image for this post is from NASA. It’s the famed bullet cluster we mentioned so many times on the show! Two galaxies clusters collided, producing the image. Hot gas from normal matter colliding and interacting is in pink, and dark matter is in blue. You can see the dark matter just flew right past everything, maintaining its spherical shape.
This composite image shows the galaxy cluster 1E 0657-56, also known as the “bullet cluster.” This cluster was formed after the collision of two large clusters of galaxies, the most energetic event known in the universe since the Big Bang. Hot gas detected by Chandra in X-rays is seen as two pink clumps in the image and contains most of the “normal,” or baryonic, matter in the two clusters. The bullet-shaped clump on the right is the hot gas from one cluster, which passed through the hot gas from the other larger cluster during the collision. An optical image from Magellan and the Hubble Space Telescope shows the galaxies in orange and white. The blue areas in this image show where astronomers find most of the mass in the clusters. The concentration of mass is determined using the effect of so-called gravitational lensing, where light from the distant objects is distorted by intervening matter. Most of the matter in the clusters (blue) is clearly separate from the normal matter (pink), giving direct evidence that nearly all of the matter in the clusters is dark. The animation below shows an artist’s representation of the huge collision in the bullet cluster. Hot gas, containing most of the normal matter in the cluster, is shown in red and dark matter is in blue. During the collision the hot gas in each cluster is slowed and distorted by a drag force, similar to air resistance. In contrast, the dark matter is not slowed by the impact, because it does not interact directly with itself or the gas except through gravity, and separates from the normal matter.
In the last half hour of the show Brian and I, and our friend and fellow DJ Tristan, spoke about dark matter for a while. Honestly, the wikipedia page for dark matter is great if you’re looking for more information on the topic.
Photo credit where credit is due: X-ray: NASA/CXC/CfA/M.Markevitch et al.; Optical: NASA/STScI; Magellan/U.Arizona/D.Clowe et al.; Lensing Map: NASA/STScI; ESO WFI; Magellan/U.Arizona/D.Clowe et al.
Check out the band, Gulps! They’re a new, totally rockin’ local New Jersey band that’s playing a lot of shows.