NASA's latest Picture of the Day unveils an extraordinary sight - the supernova shock wave known as the Pencil Nebula, offering a mesmerizing glimpse into the depths of the cosmos.
This awe-inspiring image was captured by Helge Buesing, revealing a supernova shock wave racing through interstellar space at an astonishing speed of over 500,000 kilometers per hour.
Long Ripples in a Cosmic Sheet
The image, beautifully detailed and vividly colored, showcases the thin, bright, braided filaments that appear as long ripples in a cosmic sheet of glowing gas.
Discovered in the 1840s by Sir John Herschel, this narrow-looking nebula is commonly referred to as Herschel's Ray. It is officially cataloged as NGC 2736, and its modern popular name, the Pencil Nebula, was because of its pointed appearance, according to NASA.
Situated approximately 800 light-years away, the Pencil Nebula spans nearly five light-years in length, representing just a small fraction of the vast Vela supernova remnant. This remnant encompasses around 100 light-years in diameter, and it is the expanding debris cloud resulting from a star's explosion about 11,000 years ago.
The section of the shock wave observed as the Pencil Nebula initially moved at millions of kilometers per hour but has since decelerated significantly, gradually gathering surrounding interstellar material, according to NASA.
Hubble's Image of the Pencil Nebula
In a related story, NASA's Hubble Space Telescope captured another striking image of the Pencil Nebula, portraying remnants from a star that exploded thousands of years ago.
In this Hubble image, astronomers peer along the edge of the undulating gas sheet, revealing large, wispy filamentary structures, bright gas knots, and diffuse gas patches.
The luminous glow of the nebula arises from dense gas regions struck by the supernova shock wave, heating the gas to millions of degrees before subsequently cooling down and emitting optical light, according to NASA.
The colors of different nebula regions offer insights into the cooling process. Some areas remain hot, emitting blue light due to dominant ionized oxygen atoms, while cooler regions emit red light (from cooler hydrogen atoms).
This color contrast indicates the gas temperature, with the glowing nebula being visible in the image due to its emission. The Vela supernova remnant is home to a spinning pulsar at its core and is estimated to have occurred about 11,000 years ago, leaving behind a legacy of breathtaking celestial phenomena.
The supernova blast left a spinning pulsar at the core of the Vela region. Based on the pulsar's slowing rate, astronomers estimate the explosion happened roughly 11,000 years ago.
Despite the absence of historical records, the Vela supernova would have been 250 times brighter than Venus, making it visible to southern observers during daylight hours. If correct, the explosion's age implies that material from the star was ejected at nearly 22 million miles per hour, according to NASA.