Understanding the Population

Each future discovery is exciting, but scientists are also excited about what we can do with the aggregate data, with the sheer number of new discoveries that we expect. The number of near-Earth objects, for example, will go up from about 20,000 currently known to 100,000. We know of 800,000 asteroids; with LSST, we should discover 5 million more. Known trans-Neptunian objects will increase from a few thousand to about 40,000 (the LSST’s unique ability to repeatedly image the faintest objects will really help in the distant reaches of the solar system). It's also likely that we'll discover many more interstellar small bodies like `Oumuamua, though we have no idea how many there will be. Brightness and position measurements of the majority of these objects will be repeated hundreds of times with unprecedented precision.

Detecting so many objects with a single telescope is also a huge boon for inferring what's really out there. As an example, consider the hypothesis that an undiscovered planet-sized world lurks far beyond Neptune. The “Planet 9” or “Planet X” hypothesis is based on the observation that highly distant objects (like Sedna) have a preferred orbital direction. The community is still somewhat skeptical on recent results that this preferred direction is real as opposed to simply an artifact of biases in our observations. With a single mega-survey like LSST, not only will we discover many more very distant objects, we will know exactly where we looked allowing us to very confidently say whether the grouping predicted by the Planet 9 hypothesis is real or not. In addition, such distant planets could also be discovered directly by LSST, though it is not as efficient as already existing surveys.

So. Much. Data.

The sheer volume of LSST data can be likened to a tsunami. LSST will produce about 60 petabytes (60 million gigabytes) of information over the course of the 10-year survey. LSST results will require entirely new computational methods to maximize its scientific bounty. To help astronomers cope, the LSST complex will include an onsite supercomputer. Rather than working with the data in our own labs, we will take our analysis codes to the data, a new mode of operations for most of us.

Although three years remain until the survey begins, the time to prepare for the data tsunami is now. Planetary scientists have been involved in the planning stages for over a decade and we are now well organized into the LSST Solar System Science Collaboration. In addition to supporting the LSST project with guidance in planning decisions, we are beginning to organize ourselves into groups that will work together to maximize the exciting science discussed above, expecting that it will revolutionize our understanding of small bodies in the solar system.

It is thus with gratitude that we thank the Planetary Society (and other sponsors) for contributing to the annual Solar System Science Collaboration meeting that was held at the Adler Planetarium in Chicago at the beginning of June. This meeting helped ensure that we were staying on top of existing plans and making specific goals for the future. Much remains to be done, but we have identified the key areas where progress now will reap significant future returns.

Though LSST results will look more like catalogs than pretty pictures, it will provide foundational insights into the solar system as a whole. The discovery and characterization of solar system small bodies will never be the same.