Starburst Surprise: Star Birthing in Violent Galaxy Mergers

When two galaxies collide, the mingling interstellar gases are violently turbulent. Turbulence should switch off any star formation, but galactic mergers are known to be fertile grounds for stellar birthing -- what's going on? Continue reading →

When two galaxies collide, astronomers witness a frenzy of star formation creating what are known as "starburst galaxies." Although this is known, it's a little counter-intuitive; during galactic mergers, the swirling interstellar gases are so turbulent that star formation should be switched off. So what's going on?

VIDEO: We've Simulated The ENTIRE Universe

Using two of Europe's most powerful supercomputers, French astrophysicists simulated 300,000 light-years of interstellar gas inside a Milky Way-like galaxy (on the TGCC Curie supercomputer in France) and a volume of gas, 600,000 million light-years wide, inside two merging galaxies (on the SuperMUC supercomputer in Germany). Committing millions of hours of computational time, the simulation replicated the random motions of gas inside the galactic disks, resolving chaotic features fractions of a light-year across.

It is known that dense clouds of interstellar gas can collapse under mutual gravity, eventually sparking fusion and new stars. But in the turbulent wake of a galactic merger, star formation should be hindered, not accelerated. Turbulence should disrupt star forming regions, fragmenting the cloud. As these simulations prove, however, it is this turbulence that actually accelerates star birth, driving starburst galaxies.

ANALYSIS: Monster Starbursts Seen by New Radio Telescope

The researchers were able to compare the two simulations, showing that in the collision model, violent turbulence makes interstellar gases ripe for compression (and not dispersion), accelerating star birth.

"This is a big step forward in our understanding of star formation, something only made possible by the similarly major and parallel advances in computing power," said lead researcher Florent Renaud of the AIM institute near Paris. "These systems are helping us unlock the nature of galaxies and their contents in ever more detail, helping astronomers to slowly assemble their complete history."

ANALYSIS: Perpetrator of Galactic Hit-and-Run Found

Like the recent supercomputer simulation that was used to model the evolution of our Universe, this example once again proves that despite the incredible complexities that underlie astrophysical processes, computing power is rapidly becoming more capable, allowing us a high-resolution glimpse at what drives the inner dynamics of starburst galaxies.

The Antennae galaxies as imaged by the Hubble Space Telescope and the focus of new supercomputer simulations to help explain how violently turbulent "starburst galaxies" like these form.

Using data from the Hubble Space Telescope's famous Ultra-Deep Field (UDF) observation,

astronomers have been able to deduce at what age spiral galaxies acquire their spiral structure

. Since its launch in 1990, the veteran observatory has studied countless galaxies, but some of the most striking images are that of the majestic spirals that pervade the entire observable universe. In this celebration of spiral galaxies and Hubble's prowess at imaging them, we've collected some of our favorite galactic views from the space telescope's archives.

NEWS: When Did Galaxies Get Their Spirals?

In this majestic image, phenomenal detail in galaxy

NGC 2841

's spiraling dust lanes have been captured.

Spiral galaxy

NGC 5866

as seen nearly edge-on from Hubble's perspective. The dark galactic dust silhouettes the bright galactic core.


unnamed spiral galaxy

located deep within the Coma Cluster of galaxies, around 320 million light-years away in the northern constellation Coma Berenices, shows off some intricate detail in its arms.

The famous

Sombrero galaxy

(Messier 104) is an edge-on spiral galaxy -- the "rim" of the sombrero is thick lanes of dust obscuring the galaxy's starlight.


is another spiral galaxy not too dissimilar to our Milky Way. Young, bluish stars track along the galaxy's majestic arms, while older, redder stars cluster in its bright core.

This unique view of


is a combination of Hubble data and photographs taken by astrophotographer Robert Gendler.

The 'classic' spiral

Whirlpool Galaxy

gravitationally interacts with a neighboring galaxy, refining its very clear spiral arms.

To celebrate Hubble's 21st year in space, astronomers released this striking image of a pair of interacting galaxies called

Arp 273

. (Image rotated)

The 3 galaxies of

Arp 274

appear to be very close to one another, but astronomers believe that they are far apart and only overlapping from our perspective.


UGC 10214

is undergoing some violent gravitational disturbances after a suspected galactic collision. The creation of the stream of stars post-collision appear as a tail, giving the galaxy "The Tadpole" moniker.

To see full-resolution images and more detail on the galaxies showcased here, browse the mindblowing online Hubble album.