In astronomy, we study the Universe by collecting light.
The astronomers used this set of single-color images, shown along the edge, to construct the color (center) image of a ring of star clusters surrounding the core of the galaxy NGC 1512. Adding together a series of images taken with different photometric filters, it is possible to produce an image rich in colors, with essential details on temperature, dust and more.
The use of visible light alone, however, is incredibly restrictive.
Although visible light gives us a rich and varied view of objects in the Universe, it represents only a tiny fraction of the electromagnetic spectrum. The 0.4 to 0.7 micron range, which is perceptible to human sight, is only a minor drawback compared to JWST’s 0.5 to 28 micron wavelength range.
Covering only wavelengths from 400-700 nanometers, optical astronomy neglects most of the features.
The Andromeda Galaxy, the closest large galaxy to Earth, displays an enormous variety of detail depending on the wavelength or set of wavelengths of light in which it is displayed. The optical sight, top left, is also a composite of several different filters. Shown together, they reveal an astounding array of phenomena present in this spiral galaxy. Multi-wavelength astronomy can provide unexpected insights into almost any astronomical object or phenomenon.
But multi-wavelength astronomy can reveal otherwise invisible details.
The Helix Nebula, the dying remnant of a previously Sun-like star, reveals its gas distribution in visible light, but exhibits a series of obscured features that appear knotted and fragmented in infrared light. Multi-wavelength views can reveal features that do not appear in a single set of wavelengths of light.
In particular, the dusty and star-forming regions are home to spectacular phenomena just waiting to be discovered.
The Carina Nebula, shown in visible light (top) and near infrared (bottom), was imaged by the Hubble Space Telescope in a range of different wavelengths, allowing these two very different views to be constructed. Any dusty star-forming region will have spectacular features revealed by looking at it in different wavelengths of light, and this should set the stage for what JWST can and should do.
One of Hubble’s most iconic goals is the Pillars of Creation.
Located within the Eagle Nebula, a great cosmic run ends there, some 7,000 light-years away.
This 3-D visualization of the location and properties of the element that appears as the Pillars of Creation in the Eagle Nebula is actually made up of at least four different disconnected components that are located on either side of a rich star cluster: NGC 6611 neutral matter absorbs and reflects starlight, leading to its unique appearance at optical wavelengths.
Visible light showcases neutral matter, absorbing and reflecting light from surrounding stars.
This visible light image of a large section of the Eagle Nebula was taken from the ground in an amateur configuration in 2019. It reveals a number of iconic features within, including young stars and dense, dusty regions where new ones are forming. stars. The Pillars of Creation, in the center, reflects and absorbs the light of the stars, leading to its iconic appearance.
Inside, new stars are actively formed, causing the pillars to evaporate from the inside.
This largely unknown view of the Pillars of Creation shows the limits of the Hubble Space Telescope’s capabilities: reaching the near infrared to peer through the neutral matter of the pillars and into the stars that form within. Most of the stars are objects in the background, behind the pillars, but some are proto-stars that are currently forming within them.
Outside, the external stellar radiation causes neutral matter to evaporate.
By rotating and stretching the two iconic high resolution Hubble images of the tip of the tallest pillar relative to each other, the changes from 1995 to 2015 can be superimposed. Contrary to the expectations of many, the evaporation process is slow and small.
The race consists of forming new stars inside before the gas disappears completely.
The Pillars of Creation are some of the last remaining dense knots of neutral matter forming stars within the Eagle Nebula. From the outside, hot stars irradiate the pillars, evaporating the gas. Inside the pillars, matter collapses and new stars are formed, which also radiate the pillars from within. We are witnessing the last tremors of star formation within this region.
Double Hubble images, separated by 20 years, show this evolving structure.
This image compares two views of the Pillars of Creation of the Eagle Nebula taken with Hubble 20 years apart. The new image, on the left, captures almost exactly the same region as in 1995, on the right. However, the most recent image uses Hubble’s Wide Field Camera 3, installed in 2009, to capture light from incandescent oxygen, hydrogen and sulfur with greater clarity, as well as with a wider field of view. The pillars are changing very slowly over time; it should take hundreds of thousands of years to complete evaporation.
But other wavelengths of light reveal what’s going on beneath the dust.
Chandra’s unique ability to resolve and locate X-ray sources has made it possible to identify hundreds of very young and still-forming stars (known as “protostars”). Infrared observations from NASA’s Spitzer Space Telescope and the European Southern Observatory indicate that 219 of the X-ray sources in the Eagle Nebula are young stars surrounded by disks of dust and gas and 964 are young stars without these disks. If you were wondering, no supernova remnants have been discovered; the pillars are not destroyed.
X-ray wavelengths, from NASA’s Chandra, reveal new stars and stellar remnants.
Using Chandra, the researchers detected over 1,700 X-ray sources in the Eagle Nebula field. Two thirds of these sources are probably young stars located in the Nebula and some of them are visible in this small field of view around the Pillars of Creation. Although most of the sources do not come from within the pillars themselves, the “eye” of the larger pillar corresponds to a proto-star about 5 times the mass of the Sun.
The near-infrared views peer through the dust, exposing the young stars within.
This infrared view of the Pillars of Creation from ESO’s Very Large Telescope, an 8.2-meter terrestrial telescope, peers largely through the dust of the Pillars of Creation to reveal the stars forming within. JWST views will be much higher resolution, much more detailed, and span a much wider range of wavelengths.
Herschel’s far-infrared eyes exposed cold, neutral matter, which will later form new stars.
This Herschel image of the Eagle Nebula shows the self-emission of gas and dust from the extremely cold nebula like never before. Each color shows a different temperature of the dust, from about 10 degrees above absolute zero (10 Kelvin or minus 442 degrees Fahrenheit) for red, to about 40 Kelvin, or minus 388 degrees Fahrenheit, for blue. The Pillars of Creation are among the hottest parts of the nebula, as revealed by these wavelengths.
NASA’s Spitzer previously looked at the wavelengths of JWST.
This multi-channel infrared composite view from NASA’s Spitzer Space Telescope, taken in 2007, reveals the “pillars of creation” on the right and the “spire” or “fairy” on the left, similar to the iconic features revealed by Hubble in lengths of optical wave. JWST will greatly enhance these views, showing us details that Spitzer could only have dreamed of.
With far superior light-gathering power and resolution, it’s the perfect JWST “first science” target.
Although Spitzer (launched in 2003) predated WISE (launched in 2009), it had a larger mirror and narrower field of view. Even the first JWST image at comparable wavelengths, shown next to them, can resolve the same characteristics in the same region with unprecedented accuracy. This is a preview of the quality of science we will get with JWST.
Mostly Mute Monday tells an astronomical story in pictures, images and no more than 200 words. Talk less; smile more.