Hubble's Universe Unfiltered

  • October 7, 2016

    News from the Universe, October 2016

    by Frank Summers

    Each month, I host the Public Lecture Series at the Space Telescope Science Institute in Baltimore, Maryland. Before introducing the main speaker, I present some Hubble discoveries and other astronomical findings and events called "News from the Universe".

    The stories I covered for the October 4, 2016 lecture are:

    -- The detection of possible water plumes on Europa

    -- The end of the Rosetta mission



    Here are the description and links to the main speaker's presentation for the October 2016 Public Lecture Series:

    A Multi-wavelength View of Stellar Life and Death in M83

    William Blair, Johns Hopkins University

    Although the timescales are long by human standards, galaxies undergo changes as stars are born, grow old, and ultimately die in supernova explosions. While we can't standby and watch these developments take place, we can piece together the processes involved just by looking at carefully selected snapshots in time. Messier 83, the Southern Pinwheel galaxy, is a case in point. This galaxy is home to both significant new star formation and at least 7 supernova explosions in the past 100 years. Both stellar birth and stellar death can be studied, and often require observations in different bands of light with both ground and space-based telescopes. Dr. Blair will describe a multi-year, multi-wavelength study of galaxy M83 that has provided detailed insights about its evolution.


    An archive of lecture webcasts back to 2005 is available at STScI Webcasting: STScI Public Lecture Series Archive.

    Most lectures since spring 2014 are also in a HubbleSiteChannel YouTube playlist: STScI Public Lecture Series Playlist


  • September 23, 2016

    A Hubble Journey from IMAX to 4K UHD

    by Frank Summers

    Way back in 2003, I had a summer intern who demonstrated an abundance of enthusiasm and gumption. As befits such passion, I assigned him a particularly ambitious project: attempt to extract thousands of individual galaxy images from a Hubble image with hundreds of millions of pixels. His excellent work showed that the project was indeed feasible, and that a spectacular visualization could be made with the resulting data set. We also learned that the video resolution of the time (640x480 pixels) was entirely inadequate to handle such high-resolution imagery.

    Thus, in the fall, we embarked on an even more ambitious project: an IMAX short film called "Hubble: Galaxies Across Space and Time." We improved and repeated the galaxy image extraction process on the final image data from the Great Observatories Origins Deep Survey (GOODS), a mosaic of more than 600 megapixels. From the roughly 30 thousand sources in the images, we crunched more than 10 thousand individual galaxies through the production pipeline. The resulting galaxy images, along with distances measured by the GOODS team, enabled us to create a 3D model of the galaxy distribution.

    A flight through this data set provides a visual experience of the changes in galaxies across the cosmos. In addition, because light takes billions of years to cross the intervening space, the distant galaxies are seen as they were when the light left them, billions of years ago. Thus, the journey is both across space and back in time.



    We were tremendously pleased with the result. Our small team, using 100% Hubble images and data, was able to produce a compelling visualization on the largest of screens. When it premiered at the Maryland Science Center in April 2004, I felt an awe-inspiring, "floating through the universe" immersion that was unlike anything I'd experienced before. Fortunately, folks who are not astronomy geeks were also impressed; the film won the Large Format Cinema Association's "Best Short Film" award in 2004.

    I have since shown this film in talks hundreds of times, but always with the disclaimer that it is "just so much better at full resolution." Well, today that changes. Today, we are releasing the film at 4K Ultra High Definition (UHD) resolution (3840 x 2160 pixels) on our HubbleSiteChannel on YouTube with movie file downloads available on the HubbleSite Videos page. This UHD version of the film has about 70% of the width of the master frames used to create the IMAX film prints. It is necessarily cropped in height to fit the now-standard 16x9 aspect ratio (the master frames are closer to the old standard 4x3 aspect ratio). Most importantly, this high-resolution format has 27 times as many pixels as the 640x480 resolution format we released to the public in 2004.

    Watching the film on a large screen at full 4K UHD is the first time I've approached the theater experience. The level of detail and the resulting feel of depth within the galaxy collection pull me into the scene that much more. After all the time spent processing the images, building the 3D models, and choreographing the camera, it is an absolutely wonderful surprise when I can still see something new in the end product. Although this film was completed more than a decade ago, the new technology has brought renewed enthusiasm about the possibilities for these cosmic visual explorations. What more might we do with the current, larger Hubble cosmology projects? We have even created a 6K UHD resolution (5760 x 3240 pixels) version of this film for the NASA Hyperwall that I'm just dying to try out at Goddard Space Flight Center.

    Our team has produced several other 4K UHD visualizations, and will continue to work on new ones. For more, check our Ultra HD Astronomy Visualizations playlist on YouTube or utilize the 4K-UHD Video tag on HubbleSite.

  • September 16, 2016

    Thousands of Galaxies in the GOODS/ERS2 Field

    by Frank Summers

    Looking deeply into the cosmos with Hubble, astronomers can see all sorts of galaxies. Some are large and nearby, with the familiar spiral and elliptical shapes. Others are small and distant, with dotted, elongated, and/or irregular structures. This long exposure, from the Great Observatories Origins Deep Survey (GOODS), showcases the wide variation in galaxy shapes, sizes, and colors seen across the universe.

    One of the reasons this image is so colorful is that it goes beyond the wavelengths that the human eye can see (visible or optical light). This survey was also done in the shorter wavelength ultraviolet light, as well as the longer wavelength infrared light. Astronomers are studying these galaxies across all the wavelengths Hubble can observe in order to get a fuller picture and fuller understanding of their structures.

    The change of structures with distance is extremely important, as it also indicates how galaxies change over time. The light from a galaxy five billion light-years away has taken five billion years to traverse the intervening space, and thus we see that galaxy as it was five billion years ago. Looking out into space is also looking back into time.

    The history of galaxy development is contained in these images. Nearby galaxies show the familiar patterns of what I'll call adult galaxies. More distant galaxies are, on average, younger and show the development of galaxies through their teen years. The most distant galaxies seen by Hubble are the child galaxies, with very incomplete development and only the indications of their future potential. The GOODS survey and others have systematically imaged, categorized, and tracked the changes in galaxies over time to learn how our Milky Way and its brethren went from tiny stellar and gaseous clumps to vast galactic swarms.

    But the story is not written plainly in these images. The expansion of the universe stretches the light waves that travel across this expanding space. Hence, light that starts out as visible light can be stretched to infrared wavelengths by the time we observe it. Similarly, ultraviolet light can be stretched to visible light, or even beyond to infrared light. This cosmological redshift adds in a color shift for each galaxy according to its distance from us. The deconvolution of color information is an important consideration in comparing images and observed structures. It is also a major motivation for doing such multiwavelength studies.

    Finally, I'll note that cosmological redshift pushes the most distant galaxies outside of Hubble's reach. The light from the most distant galaxies, the baby galaxies if you will, has had their light redshifted so far into the infrared regime that Hubble cannot observe them. NASA's current infrared observatory, the Spitzer Space Telescope, does observe at those wavelengths, but lacks the angular resolution to discern such tiny sources. To see these galaxies requires a telescope with the same keen resolution of Hubble, and extending to the infrared wavelengths of Spitzer. That is the James Webb Space Telescope, which will launch in October 2018.

    Images like this can be mesmerizing for astronomers. The diversity of shapes and sizes and colors are cool to explore for most anyone. Now add on top of that an exploration of galaxy development across both space and time. The visual and intellectual adventure can be truly intoxicating.

    A high-resolution version (18 megapixels) of this image is available on the HubbleSite press release pages. Enjoy!