Film & Animation

Perspectives on Spiral Galaxies

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Spiral galaxies are pancake-shaped collections of billions of stars, along with vast clouds of gas and dust. This video illustrates how their observed shapes can differ greatly depending upon the angle at which they are observed. The spiral galaxies NGC 4302 (left) and NGC 4298 (right) are visualized in three dimensions and rotated to showcase how they might look if viewed from other perspectives. Each galaxy could be seen as a roughly circular face-on spiral, as a long, thin, edge-on spiral, or as any of the oblong shapes in between.

The galaxy models are based on observations by the Hubble and Spitzer space telescopes, as well as on the statistical properties of galaxies. Because NGC 4302 is seen nearly edge on, and its structure is not well-defined, its model was based upon observations of the spiral galaxy Messier 51.

Credit: NASA, ESA, F. Summers, J. DePasquale, Z. Levay, and G. Bacon (STScI)

3D Spectroscopy and the Dynamics of Galaxies

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Most people are familiar with how a prism splits the light of the Sun into its component rainbow of colors. Research astronomers use instruments called spectrographs to split the light from celestial objects and measure its intensity at different wavelengths. These spectral observations can be used to determine temperature, composition, motion, and more. Imaging spectrographs extend the entire 2D view of an image into a third dimension of wavelength, and have greatly expanded the capacity to map the motions of gas and stars within galaxies. Dr. Law will present the history of this powerful type of instrument, highlight what it has taught us about the evolution of galaxies over the last 12 billion years, and discuss some of the exciting science that such instruments on board the James Webb Space Telescope are expected to deliver in the near future.

Speaker: David Law, Space Telescope Science Institute
Host: Dr. Frank Summers

Recorded live on April 4, 2017 from the Space Telescope Science Institute in Baltimore, MD, USA.

MORE INFO: http://hubblesite.org/about_us/public_talks/

STScI Webcast Links:
Frank Summers ­- News from the Universe:
https://webcast.stsci.edu/webcast/detail.xhtml?talkid=5583

David Law – 3D Spectroscopy and the Dynamics of Galaxies:
https://webcast.stsci.edu/webcast/detail.xhtml?talkid=5582

Tonight’s Sky: April 2017

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Backyard stargazers get a monthly guide to the northern hemisphere’s skywatching events with “Tonight’s Sky.” Skies should be fairly dark for this year’s annual “April shower.”

“Tonight’s Sky” is produced by HubbleSite.org, online home of the Hubble Space Telescope. This is a recurring show, and you can find more episodes — and other astronomy videos — at HubbleSite.org.

Visit Tonight’s Sky on HubbleSite:
http://hubblesite.org/videos/tonights_sky