April 16, 2021 6 min read
Located 7,000 light-years away from Earth within The Eagle Nebula (M16/NGC 6611), the Pillars of Creation are one of the most iconic Hubble Space Telescope photos of all time. It won't surprise you to hear that it made our Top 10 List of the Best Hubble Telescope Images.
The Pillars of Creation "are part of an active star-forming region within the nebula and hide newborn stars in their wispy columns."
How exactly does star formation take place within such a region? How do we get from clumps and clouds of gas, to the enormous thermonuclear powerhouses known as stars?
Brandon Spekter, Senior Writer for LiveScience.com, explains:
"As ever greater quantities of gas and dust pile into a single, gravitationally-dense area, that area heats up under the weight of the gathering material and may turn into the seeds of a star — also called a 'protostar.' If a protostar continues gathering mass and increasing in temperature enough to spark a nuclear reaction at its core, a full-fledged star is born."
Consider that in regions such as these, what starts out as little more than cool hydrogen gas in the frigid vacuum of outer space—through gravity and pressure alone—gets compressed and heated to such an extreme degree that ultimately stars are formed, whose interior temperatures reach tens of millions of degrees. All of that, from just some cold interstellar gas, plus gravity & time.
Whenever we look at an astronomy image like this, it's usually very difficult for our brain to comprehend the size of what we're looking at. We learn in a NASA article that the Pillars of Creation are about 4 to 5 light-years tall. What this means is that if we were inside of a hyper-advanced spaceship that was capable of traveling at the speed of light—which is the fastest attainable speed in the universe—it would take us 5 full years of our life just to travel from the bottom to the top of one of these pillars.
A good way to try to put their size in perspective is to look at before & after Hubble images of the Pillars, with one set taken in 1995, the other in 2014.
As we can see here in this image, the section on the left is already a zoomed-in portion of the Pillars. Then we zoom in even further on just a sub-section of that already zoomed-in region. There we see "'a narrow jet-like feature' has stretched 60 billion miles at a rate of 450,000 miles per hour between 1995 and 2014."
So that seemingly tiny distance between the 1994 and 2014 arrows on the image? That is 60 billion miles right there. In other words, if you were moving non-stop at 450,000 miles per hour for 20 continuous years, that's as far as you would have made it within The Pillars of Creation.
". . . new observations captured a portrait of the pillars in infrared light, as well as in visible light. The longer wavelengths of infrared light pass more easily through the dusty environs, allowing us to see more of the wispy details and the stars normally hidden inside or behind the pillars when viewed in visible light."
NASA encourages us to take a closer look at this infrared image to see what it really reveals to us:
"In this ethereal view the entire frame is peppered with bright stars and baby stars are revealed being formed within the pillars themselves."
Also interesting is to see the Pillars of Creation within the broader context of the full Eagle Nebula that they're situated within, as seen here within this Astronomy Picture Of The Day:
No matter how massive an object you're looking at the universe, you can always zoom out another level and make it look comparatively tiny within the larger scheme of things. It brings to mind that famous Star Wars line that "There's always a bigger fish."
You think that Eagle Nebula image is cool? Prepare to have your mind absolutely blown into pieces by this Hubble/ESA video, which slowly zooms all the way in on The Pillars Of Creation from a starting point of our visual field on Earth:
The BBC also has this really cool 3D visualization of The Pillars of Creation, this one with accompanying narration as well.
The ESO's Very Large Telescope provides another way to visualize The Pillars: a 3D mapping to show the relative distribution of the respective Pillars. The ESO explains as follows:
"Using the MUSE instrument on ESO’s Very Large Telescope (VLT), astronomers have produced the first complete three-dimensional view of the famous Pillars of Creation in the Eagle Nebula, Messier 16. The new observations demonstrate how the different dusty pillars of this iconic object are distributed in space."
While the Pillars of Creation are a proto-typical example of star creation and formation, they're also simultaneously an example of destruction, as well. Hadley Pratt explains:
". . . a group of massive, young stars . . . is illuminating the entire scene from above, and slowly destroying it. The ultraviolet light from new stars erodes the pillars of dust and gas in a process called photo-erosion.
'The gas is not being passively heated up and gently wafting away into space. The gaseous pillars are actually getting ionized (a process by which electrons are stripped off of atoms) and heated up by radiation from the massive stars. And then they are being eroded by the stars’ strong winds (barrage of charged particles), which are sandblasting away the tops of these pillars.'"
Some scientists argue that a nearby supernova shockwave may have actually destroyed the Pillars of Creation already—yet due to their distance from the Earth at about 7,000 light-years, we simply haven't witnessed it yet. The controversy on this point is explained in a New Scientist article:
("The hot dust linked to a supernova explosion is shown as red in this false-color composite," quoted from Astronomy magazine.)
". . . an infrared image from the Spitzer Space Telescope has revealed a previously unseen supernova blast wave that was advancing towards the pillars at that time, threatening to ultimately sweep them away.
Nicolas Flagey of the Institut d’Astrophysique Spatiale in Orsay, France, led a team that obtained the image. It shows a cloud of hot dust thought to have been heated by a supernova blast that likely occurred between 1000 and 2000 years earlier.
Based on the cloud’s position, the blast wave looked set to hit the pillars in 1000 years. Taking into account the 7000-year time lag for their light to reach the Earth, that means the pillars were actually destroyed 6000 years ago, Flagey says.
We will not see their obliteration from Earth for another 1000 years, however. And when we do, they will be in tatters – Flagey says only a few patches of the pillars are dense enough to survive the blast. 'All the other parts will crumble when the shock wave arrives,' he says.
. . . But Stephen Reynolds of North Carolina State University in Raleigh, US, is not convinced the hot dust cloud is the result of a supernova explosion. The expanding gas, or remnant, from the event should emit much stronger radio waves and X-rays than have been observed, he says.
'I believe that a supernova remnant less than 2000 years old at a distance of less than 6000 light years would have to have quite unusual properties to have avoided detection to this point,' he told New Scientist.
Instead, he suggests that hot, high-speed winds from massive stars in the region could have heated up the dust grains in the cloud. If so, the presence of this hot gas would still erode the pillars of creation over time, he says."
So whether it happens quickly or it happens slowly, the Pillars of Creation appear to be doomed either way. The good news is, worst-case scenario, we won't witness this destruction until at least 1,000 years from now. And on top of that, regardless of what happens, The Pillars of Creation are forever immortalized within these classic Hubble images.
April 13, 2021 6 min read