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The Sciences

Peering into the future

Cosmic VarianceBy Daniel HolzAugust 18, 2010 7:14 PM


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The big news this week in astrophysics is not the discovery of a new planet. Nor is it the first glimpse of a galaxy on the other side of the Universe. It's much more important: the arrival of the latest Decadal Report. It all started over a year ago, and fellow blogger Julianne has been a major participant.


The full report is an excellent description of the entire field, both where we are now, and where we're likely to be headed. If 200+ pages is a bit much to swallow, the report contains a 5 page Executive Summary (with 5 tables laying out the project rankings and costs). Probably the best place to start, however, is Julianne's discussion of the report: post 1, post 2, and post 3. For those with no attention span whatsoever, here is my 6 bullet-point summary: 1. Surveys rule the roost. The next decade is about survey telescopes. The #1 space priority is an infrared survey telescope (WFIRST) (a successor of SNAP/JDEM). The #1 ground priority is a wide-field optical survey telescope (LSST). 2. Another golden decade of cosmology (and planets). Both the top space and ground priorities originated as dark energy/cosmology missions. They turn out to be excellent planet missions as well. 3. Bang for the buck. Smaller, diverse, rapid-response programs provide excellent science return. The "Explorer program" and the "Mid-scale Innovations Program" are the #2 priorities for space and ground, respectively. Specific missions within these programs are unspecified. 4. The birth of gravitational-wave astronomy. We are (hopefully) entering the decade of gravitational-wave astrophysics. The Laser Interferometer Space Antenna (LISA) is the 3rd ranked space mission. This is a big deal: gravitational-waves have yet to be seen, but the astronomical community nonetheless recognizes and prioritizes the role they have to play in exploring our Universe. 5. Clash of the Titans. The 3rd priority for ground-based astronomy is a huge (30 meter) optical/infrared telescope. There are two projects well underway (GMT and TMT). The report encourages the NSF to pick one for federal investment. 6. Etcetera. Other things that are discussed include an X-ray telescope (IXO), a high-energy gamma ray telescope (ACTA), a submillimeter telescope (CCAT), and a number of smaller missions and projects (including full funding for NASA's Astrophysics Theory Program). Note that the Hubble Space Telescope's successor, the James Webb Space Telescope (JWST), is not extensively discussed in this report, since it is already funded and is on track for launch in the next few years. I'm excited about all of these facilities. I've written papers related to many of them (JDEM, LISA, and LSST), and I am convinced they will all profoundly deepen our understanding of our Universe. The Decadal report represents a tremendous investment by the astro community, involving hundreds of scientists making extremely painful and difficult choices. At the end of the day, a clear ranking has been produced, and a strong case has been articulated. Now the task it to convince the full astronomy community, Congress, and the taxpayers that we have done our homework, and that these missions are worthy of major public investment. We have an incredible decade ahead of us!

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