The Helix Nebula glows 650 light-years from Earth, revealing intricate filaments, colorful gases, and the remains of a dying Sun-like star.
Today’s Image of the Day from NASA reveals the Helix Nebula, a vast shell of glowing gas left behind by a dying star about 650 light-years from Earth.
Astronomers have concluded that we are looking almost directly down a tremendous cylinder of glowing gas, rather than at a simple bubble floating in space.
Looking into the Helix NebulaThe Helix Nebula lies in the constellation Aquarius and is one of the closest planetary nebulae to Earth.
That restricted where Hubble could safely look, but the Helix Nebula happened to lie almost exactly in the opposite direction.
The Helix Nebula glows 650 light-years from Earth, revealing intricate filaments, colorful gases, and the remains of a dying Sun-like star.
Today’s Image of the Day from NASA reveals the Helix Nebula, a vast shell of glowing gas left behind by a dying star about 650 light-years from Earth.
At first glance, the nebula resembles a colorful cosmic eye staring back at us. Its apparent ring, however, is partly an illusion of perspective.
Astronomers have concluded that we are looking almost directly down a tremendous cylinder of glowing gas, rather than at a simple bubble floating in space.
Looking into the Helix Nebula
The Helix Nebula lies in the constellation Aquarius and is one of the closest planetary nebulae to Earth.
Its relative proximity makes it appear enormous in our sky. The nebula spans nearly half the apparent diameter of the full Moon, even though its faint glow makes it far harder to see.
At its distance from Earth, that apparent size corresponds to a ring nearly three light-years across.
The portrait combines observations from the Hubble Space Telescope with a much wider view captured by the Mosaic Camera on the National Science Foundation’s 0.9-meter telescope at Kitt Peak National Observatory in Arizona.
Hubble could not capture the entire sprawling structure in a single exposure.
Astronomers used its Advanced Camera for Surveys to take multiple images, which were assembled into a mosaic and blended with the wider ground-based view.
The result exposes structures that would otherwise be difficult to see across the entire nebula.
Thousands of strange filaments
Along the inner edge of the Helix are thousands of narrow structures that resemble tiny comets.
Each appears to have a dense head followed by a long tail, with the structures pointing back toward the star at the center of the nebula.
Ground-based astronomers had known about these features for decades, but Hubble revealed them in remarkable detail.
They formed as hot gas flowing away from the dying central star encountered cooler material that the star had expelled earlier in its life.
The interaction helped sculpt the surrounding gas and dust into the intricate structures visible today.
Astronomers have suggested that the comet-like filaments could lie within a disk surrounding the central star, forming something like an enormous collar around it.
Colors reveal glowing gases
The dramatic colors in the image are not simply decorative. They trace different elements glowing within the nebula.
Blue marks light associated with oxygen, while the red regions trace hydrogen and nitrogen.
Together, these gases form the bright ring surrounding the small but extremely hot stellar remnant at the center.
That central object is a white dwarf, the exposed core left after the original star shed much of its outer material.
The Helix therefore offers a preview of a possible distant future for our own solar system.
Stars similar in mass to the Sun eventually exhaust the fuel sustaining their interiors. As they approach the ends of their lives, they can cast their outer layers into space, exposing their hot cores.
Radiation from the remaining star then illuminates the expanding material around it.
A planetary nebula has no planets
Despite the name, planetary nebulae have nothing to do with the formation of planets.
The term dates back to early telescope observations. Through small instruments, these round, fuzzy objects could resemble the disks of planets, and the name remained even after astronomers understood their true nature.
With more powerful telescopes, structures hidden within those fuzzy patches become visible.
In the Helix, what looks like a doughnut-shaped ring is actually part of a much more complicated three-dimensional structure.
The glowing tube extends an enormous distance through space and happens to be oriented nearly toward Earth. That alignment gives us the unusual perspective seen in the image.
Hubble found an unexpected opportunity
The circumstances behind Hubble’s observations of the Helix were unusual.
During the Leonid meteor storm in November 2002, spacecraft controllers needed to protect Hubble from the stream of particles passing through Earth’s neighborhood.
They pointed the observatory’s more protected rear section toward the incoming meteor stream.
That restricted where Hubble could safely look, but the Helix Nebula happened to lie almost exactly in the opposite direction.
Rather than leaving the telescope idle, astronomers used the opportunity to observe the nebula.
Hubble spent nine orbits photographing the Helix and captured nine separate snapshots needed to cover its enormous apparent size.
Those observations ultimately became part of one of the most detailed portraits of this nearby stellar graveyard.
Image Credit: NASA, ESA, C.R. O’Dell (Vanderbilt University), M. Meixner and P. McCullough (STScI)
—–
Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates.
Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.
—–
