In the year 1054 AD, Chinese sky watchers witnessed the sudden appearance of a "new star" in the heavens, which they recorded as six times brighter than Venus, making it the brightest observed stellar event in recorded history. This "guest star," as they described it, was so bright that people saw it in the sky during the day for almost a month. Native Americans also recorded its mysterious appearance in petroglyphs.
Observing the nebula with the largest telescope of the time, Lord Rosse in 1844 named the object the "Crab" because of its tentacle-like structure. But it wasn't until the 1900s that astronomers realized the nebula was the surviving relic of the 1054 supernova, the explosion of a massive star.
Now, astronomers and visualization specialists from the NASA's Universe of Learning program have combined the visible, infrared, and X-ray vision of NASA's Great Observatories to create a three-dimensional representation of the dynamic Crab Nebula. Certain structures and processes, driven by the pulsar engine at the heart of the nebula, are best seen at particular wavelengths.
The multiwavelength computer graphics visualization is based on images from the Chandra X-ray Observatory and the Hubble and Spitzer space telescopes. The approximately three-minute video dissects the intricate nested structure that makes up this stellar corpse, giving viewers a better understanding of the extreme and complex physical processes powering the nebula. The powerhouse "engine" energizing the entire system is a pulsar, a rapidly spinning neutron star, the super-dense crushed core of the exploded star. The tiny dynamo is blasting out blistering pulses of radiation towards us 30 times a second with unbelievable clockwork precision.
The movie begins by showing the Crab Nebula in context, pinpointing its location in the constellation Taurus. This view zooms in to present the Hubble, Spitzer, and Chandra images of the Crab Nebula, each highlighting one of the nested structures in the system. The video then begins a slow buildup of the three-dimensional X-ray structure, showing the pulsar and a ringed disk of energized material, and adding jets of particles firing off from opposite ends of the energetic dynamo.
Appearing next is a rotating infrared view of a cloud enveloping the pulsar system, and glowing from synchrotron radiation. This distinctive form of radiation occurs when streams of charged particles spiral around magnetic field lines. There is also infrared emission from dust and gas.
The visible-light outer shell of the Crab Nebula appears next. Looking like a cage around the entire system, this shell of glowing gas consists of tentacle-shaped filaments of ionized oxygen (oxygen atoms missing one or more electrons). The tsunami of particles unleashed by the pulsar is pushing on this expanding debris cloud like an animal rattling its cage.
The X-ray, infrared, and visible-light models are combined at the end of the movie to reveal both a rotating three-dimensional multiwavelength view and the corresponding two-dimensional multiwavelength image of the Crab Nebula.
The three-dimensional interpretation is guided by science data and evidence, scientific knowledge and intuition, and artistic license. Starting with the two-dimensional Hubble, Spitzer, and Chandra images, the team worked with experts to analyze the complex nested structures comprising the nebula and identify the best wavelength to represent each structure.
The three-dimensional structures serve as scientifically informed approximations for visualizing the nebula. The nested structures show that the nebula is not a classic supernova remnant, as once commonly thought, but that the system is better classified as a pulsar wind nebula. A traditional supernova remnant consists of a blast wave, and debris from the supernova that has been heated to millions of degrees. In a pulsar wind nebula, the system's inner region consists of lower-temperature gas that is heated up to thousands of degrees by the high-energy synchrotron radiation.
The visualization is one of a new generation of products and experiences being developed by the NASA's Universe of Learning program. The effort combines a direct connection to the science and scientists of NASA's Astrophysics missions with attention to audience needs to enable youth, families, and lifelong learners to explore fundamental questions in science, experience how science is done, and discover the universe for themselves.
This video demonstrates the power of multiwavelength astronomy. It helps audiences understand how science is done—how and why astronomers use multiple regions of the electromagnetic spectrum to explore and learn about our universe.
Frank Summers and the STScI visualization team worked with Robert Hurt, lead visualization scientist at IPAC, on the Spitzer images; and Nancy Wolk, imaging processing specialist at the Chandra X-ray Center at the CfA, on the Chandra images. NASA's Universe of Learning materials are based upon work supported by NASA under cooperative agreement award number NNX16AC65A to the Space Telescope Science Institute, working in partnership with Caltech/IPAC, Jet Propulsion Laboratory, CfA, and Sonoma State University.
NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge and Burlington, Massachusetts, controls Chandra's science and flight operations.