Mapping the Universe
In Search of Nearby Worlds


I specialize in making and analyzing full-sky, high-resolution maps from large astronomical imaging data sets. Much of my work focuses on processing infrared images from NASA's NEOWISE mission, repurposing this vast asteroid-hunting data set for astrophysics beyond the main belt. I am using NEOWISE data to search for cold nearby worlds, such as the hypothesized Planet Nine, Planet X, and other elusive neighbors to the Sun which may be impossible to find at visible wavelengths.

WISE Planet Nine Search

I have performed the deepest and widest area WISE-based search for Planet Nine.

Backyward Worlds: Planet 9

I co-founded this citizen science motion search, built around my WISE coadds.

WISE Coadds

I've reprocessed 140 terabytes of WISE images to create the deepest ever full-sky maps at 3-5 microns.


A W1/W2 successor to AllWISE based on my WISE coadds.

DESI Imaging Surveys

I'm a core member of the DESI imaging surveys team, producing optical catalogs 1.5-2 mags deeper than SDSS over 14,000 square degrees of sky.

WISE Dust Map

I created a full-sky, high-resolution map of mid-infrared dust emission.


My work, particularly in relation to Planet Nine, has been widely featured in local, national and international media. A partial list of articles quoting or mentioning me by name is provided below. I was was also interviewed for a TV segment on San Francisco's KPIX5 (CBS), and radio segments on Bay Area stations KGO and KCBS.

Berkeley News : UC Berkeley, NASA looking for citizen scientists to help find Planet 9 : NASA-funded Website Lets Public Search for New Nearby Worlds
Berkeley Lab : Attention Earthlings: Help Wanted in Finding a New Planet
USA Today : NASA wants you - to find a missing planet
New York Post : NASA would like you to please find this planet
Daily Mail : Can YOU spot Planet 9?
Die Welt : Jeder soll bei der Jagd auf Planet Neun mithelfen


I co-founded Backyard Worlds: Planet 9, a Zooniverse project consisting of an all-sky crowdsourced motion search built around my time-resolved WISE/NEOWISE coadds. Since launching in February 2017, over 100,000 citizen scientists have contributed to our total of more than 4 million classifications. Backyward Worlds now counts 40,000 registered users, and has benefited enormously from the enthusiasm and dedication of our diverse group of volunteers, some of whom have gone on to receive media recognition for their participation. Four citizen scientists are co-authors on the project's first peer-reviewed publication.

Credit: NASA's Goddard Space Flight Center Conceptual Image Lab/Krystofer D.J. Kim