Travel the universe with Dr. Ethan Siegel as he answers the biggest questions of all
By time you see a pillar at all, almost all of your ‘formation’ is already finished.
In the heart of the Eagle Nebula, the iconic Pillars of Creation loom as one of Hubble’s greatest all-time sights.
The Eagle Nebula contains thousands of new stars, a brilliant central star cluster, and various evaporating gaseous globules containing active star formation and brilliant young stars of their own. The gaseous regions are in the process of evaporating. (NASA / ESA & HUBBLE; WIKISKY TOOL)
But very little is still being created in there, compared to the destruction that’s taking place.
Using Chandra, researchers detected over 1,700 X-ray sources in the field of the Eagle Nebula. Two thirds of these sources are likely young stars located in the Nebula, and some of them are seen in this small field of view around the Pillars of Creation. There is no evidence here, or in the surrounding environment, of a recent supernova. (X-RAY: NASA/CXC/INAF/M.GUARCELLO ET AL.; OPTICAL: NASA/STSCI)
It’s true: there are new stars being formed inside, as the gas gravitational collapses down to grow the largest clumps of matter.
The pillars of creation (left) and the fairy (upside down, top right) are two of the iconic features that Hubble has imaged. Within, new stars still form as the gas and dust evaporates, but it’s largely the stars external to these nebulous regions that are boiling away the gas clumps. (ESO / VST SURVEY)
But the reason you have a pillar shape at all is because of nearby, bright, external stars, which boil the gas away.
The Herschel Space Observatory captured this image of the Eagle nebula, with its intensely cold gas and dust. The “Pillars of Creation,” made famous by NASA’S Hubble Space Telescope in 1995, are seen inside the circle. The different colors represent gas that’s extremely cool: between 10 and 40 K. (ESA/HERSCHEL/PACS/SPIRE/HILL, MOTTE, HOBYS KEY PROGRAMME CONSORTIUM)
Wherever you find a pillar-like shape, what you’re seeing is a dense region of light-blocking gas and dust.
The VLT’s ANTU telescope imaged the famous Pillars of Creation region and its surroundings in near-infrared in 2012. This enabled astronomers to penetrate the obscuring dust in their search to detect newly formed stars. The near-infrared results showed that some (11 of the 73) evaporating gas globules detected possibly contained stars, and that the tips of the pillars contain stars and nebulosity not seen in the Hubble image. (VLT/ISAAC/MCCAUGHREAN & ANDERSEN/AIP/ESO)
But pillars also absorb and reflect the light external to them, which is an important (and often overlooked) component.
In a combined image that doesn’t include visible-light data, the gas globules truly stand out. However, they are transient and temporary, and will be fully evaporated only a few thousand years into the future.(NASA/JPL-CALTECH)
Surrounding dying stars and nearby newly-formed stars, these dense clumps of matter are the last remnants of neutral gas.
Star-forming regions, like this one in the Carina Nebula, can form a huge variety of stellar masses if they can collapse quickly enough. Inside the ‘caterpillar’ is a proto-star, but it is in the final stages of formation, as external radiation evaporates the gas away more quickly than the newly-forming star can accrue it. (NASA, ESA, N. SMITH, UNIVERSITY OF CALIFORNIA, BERKELEY, AND THE HUBBLE HERITAGE TEAM. STSCI/AURA)
External ultraviolet radiation causes these clumps to ionize and evaporate, eventually leading to their expulsion.
The Eagle Nebula, famed for its ongoing star formation, contains a large number of Bok globules, or dark nebulae, which have not yet evaporated and are working to collapse and form new stars before they disappear entirely. The Pillars of Creation are just one many examples of gaseous evaporation happening all over the place in star-forming regions such as the Eagle Nebula. (ESA / HUBBLE & NASA)
Scientifically, we call these knots of neutral matter EGGs: Evaporating Gaseous Globules.
Gas and dust in the nebula IC 2944, along with new stars. The evaporation of these gaseous globules is all but certain, due to the external ultraviolet radiation coming from the surrounding hot stars. Any stars forming inside these globules had better finish what they’re doing quickly; they’ll be gone in well under a million years. (NASA/ESA AND THE HUBBLE HERITAGE TEAM (STSCI/AURA))
There may be proto-stars inside, but they’re running out of time.
Star birth in the Carina Nebula, in the optical (top) and the infrared (bottom). The hottest stars emit the most UV light, and are responsible for what astronomers call ‘quenching star formation,’ which means they remove the potential fuel from these actively star-forming regions very quickly. (NASA, ESA AND THE HUBBLE SM4 ERO TEAM)
In the cosmic race between gravitation and evaporation, the latter is faster.
This spectacular image of the Orion Nebula star-formation region was obtained from multiple exposures using the HAWK-I infrared camera on ESO’s Very Large Telescope in Chile. New stars are still forming in this nebula, but they’re almost done doing so, as the hot, young stars are boiling all potential star-forming gas away. (ESO/H. DRASS ET AL.)
New stars may form, but 99% of star creation has already completed.
The Trifid Nebula, like many star-forming regions we know of, consists of an alarming number of new stars, but also a spectacular view of pillar-like objects. The proto-stars forming inside have only a few hundred thousand years, at most, to finish forming before the ultraviolet radiation from already-existing stars finished blowing that potentially star-forming gas away. (NASA/JPL-CALTECH/J. RHO (SSC/CALTECH))
Mostly Mute Monday tells the astronomical story of a scientific object, class, or phenomenon in images, visuals, and no more than 200 words. Talk less; smile more.
