A familiar space picture has another way in: press play.
NASA’s Astronomy Picture of the Day feature for 18 October turns the spotlight on a sonification of the Eagle Nebula’s famous pillars. Instead of asking you only to look at columns of gas and dust, it offers a way to follow their structure through sound.
No microphone was sent into the nebula. The audio is made by mapping information in astronomical images into sound, a process called sonification.
The latest feature revisits an older project. It is not the announcement of a newly recorded cosmic noise or a new observation taken this weekend.
The picture becomes a kind of score
In the Pillars of Creation piece, a scan moves from the left side of the image to the right. Position in the image helps determine what a listener hears.
The Chandra X-ray Center’s explanation says the vertical position of the light controls pitch. Features higher in the picture are translated differently from those lower down, allowing the changing outlines of the pillars to produce sweeping changes in sound.
The project combines optical information associated with Hubble and X-ray information from Chandra. The two can be experienced individually or together.
That separation is useful. Rather than treating the result as background music, a listener can compare which features appear in each layer and how their combination changes the experience.
The scanning direction is a design choice for reading the image. It does not mean a wave is physically travelling across the nebula at the speed shown in the video.
Why a point of light can sound different from a pillar
A bright dot and an extended cloud do not occupy the image in the same way. The sonification uses that difference.
Chandra describes compact sources as producing brief, relatively pure tones. Extended structures, including the pillars, create broader, noisier sounds because they contain a range of frequencies.
That gives the listener more than one clue. Pitch helps encode position, while the character and spread of the sound can help distinguish concentrated points from larger structures.
You do not need to memorise every astronomical name before trying it. Start with the simple relationship between the scan and the picture, then notice where a short sound gives way to a more sustained texture.
The explanation is important because there is no single natural musical instrument assigned to every object in space. The rules are chosen to represent the particular dataset.
Those grand-looking columns are not solid towers
The featured structures belong to a star-forming region. They are columns of cold gas and dust, rather than rock pillars standing on a surface.
NASA’s APOD description explains that radiation and powerful winds from nearby stars shape and erode them. Their striking outlines are part of an environment being changed by young stars.
A still image can make the scene look like permanent architecture. The accompanying science points to something more dynamic: material is being sculpted, illuminated and dispersed.
Sonification offers another route into noticing that structure. It does not directly measure the sound of that erosion, and a louder passage should not be interpreted as a louder storm occurring there.
The useful connection is between the data and the mapping described by the creators, not an imagined soundtrack to what an astronaut would hear beside a pillar.
Accessibility is part of the point
NASA’s wider sonification work involves scientists, musicians and people from the blind and low-vision community. The goal includes making astronomical information available through another sense.
In a NASA podcast about the project, visualisation scientist Kimberly Arcand describes selecting the scientific story first, then deciding which features and sound rules will communicate it.
That could involve translating intensity into volume or assigning different kinds of light different sounds. The mapping must preserve a meaningful relationship to the information while remaining understandable to listeners.
It is a collaboration, rather than a computer simply adding a dramatic tune to a pretty picture.
For someone who cannot use an image in the usual way, that changes how a piece of astronomy can be approached. Sighted readers can also use the audio to pay attention to features they might otherwise skim past.
You can make a version yourself
NASA’s Hearing Hubble activity takes the idea beyond a single finished video. It lets visitors choose from ten Hubble views and adjust how information becomes sound.
The controls include instruments, scanning patterns, harmony and the scientific information being mapped. Changing them makes the role of the creator easier to understand.
If a different instrument changes the mood, that does not mean the nebula has changed. You have altered the way the same visual information is represented.
That is a useful experiment for a classroom, a curious evening at home or anyone who normally scrolls past space images after a few seconds. Compare two settings and ask what became easier to notice.
NASA notes that iPhone users may need to take their device out of silent mode for Hearing Hubble’s audio to play. A silent page is not necessarily a failed sonification.
Listen with the explanation nearby
Start with the Pillars piece and read the short mapping description before playing it. Then compare the optical and X-ray versions where the project provides them.
Watch, or follow the description of, the left-to-right scan. Think about the position of each feature rather than trying to identify every note as a named star.
Next, try the interactive Hubble activity and change one setting at a time. Keeping the image fixed while changing the sound rules makes the translation easier to follow.
There is a lovely surprise here, but it is grounded in a practical idea: the same scientific information can be explored in more than one form. The next time a picture of the pillars appears on your feed, you can do more than admire the shape. You can follow how that shape has been turned into something to hear.
Sources & further reading
Prepared with AI assistance from linked reporting. The cover is an AI-generated editorial illustration. Spotted something we should correct?