NEOscan

This app helps you discover near-Earth objects (NEOs). Filter by their type (asteroid or comet), closest approach time, closest distance, and diameter.

For each NEO, the app shows you an Earth-Moon model with the asteroid (or comet) indicated at the proper location. The app also helps you understand the NEO's size by comparing it to a familiar object.

The data on NEOs is provided by NASA's Small Body Database (SBDB) and SBDB Close-Approach Data APIs.