Light, Shadows, Silhouettes

Light, Shadows, and Silhouettes

Most of what we know about the universe beyond Earth is based on observations of electromagnetic radiation, better known simply as light. Whether captured by a telescope in space or a camera on Earth’s surface, light, shadows, and silhouettes reveal interactions between energy and matter, forming snapshots of the dynamic processes shaping our universe.

              Hubble Space Telescope | 2014              Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

In the Eagle Nebula 6,500 light-years from Earth, what appear at first to be billowing clouds of smoke or giant rocky protrusions are actually the eroded remains of dense towers of dust and gas, silhouetted against starlight and hot glowing gas. Like rock formations that have been sculpted by millions of years of wind and water, the iconic Pillars of Creation have also been shaped by outside forces. Ultraviolet radiation, combined with the force of charged particles hurtling through space, have eroded the cloud, leaving behind denser, more resistant remains. Though these structures are immense—with heights hundreds of thousands of times the distance from Earth to the Sun—the stellar winds will have completely eroded them away several million years from now, exposing the stars that are currently forming deep inside.

Our ability to perceive objects and materials in the universe depends on the type of light we can observe. In visible light, the densest portions of the pillars are opaque, absorbing the surrounding light, hiding the stars beyond as well as those forming within. With NASA’s next generation of more sensitive infrared telescopes, the Webb Telescope and WFIRST, we will be able to peer even deeper into the shadows of dust to directly photograph stars in the process of being born.


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