At any given moment, experts in space science are tracking over 2,000 near-Earth objects (NEOs) that could pose a potential risk to life on Earth due to their orbital trajectories, estimated diameters, and projected velocities. NASA’s JPL Sentry System is an Earth impact monitoring system designed for comprehensive observation and collection of data regarding these objects. But how do people not intimately familiar with space science concepts engage with this information? This project seeks to make data regarding possible impact events more approachable to the everyday person, presenting different elements of Sentry’s data in ways that better contextualize the actual risk of currently monitored NEOs, the range in which potential impacts might occur, and the scale of risk currently associated with said objects.

Distribution of monitored objects across Palermo Scale risk categories

Distribution of monitored asteroids across Palermo Scale risk categories
Case Study: 2024 YR4

Each row in NASA’s sentry table represents a near-Earth Object (NEO) currently monitored by Sentry that presents any statistical chance of impacting the Earth. To illustrate what each column and data point represents, we will use the asteroid 2024 YR4 as an example, which briefly had a 3.1% chance of hitting Earth before further calculations reduced that risk to 0.00081%, generating significant media attention as a result.

Designation Breakdown
Year
2024

Year Detected

Half-Month Code
Y

2nd Half of December

Sequence Subscript
R4

117th Designation That Half-Month

Peak Probability
3.1%

Recorded Jan 2025

Current Probability
.00081%

Revised Mar 2026

Identification Data
Object

Provisional designation: Year + half-month code + sequence subscript

Last Observed

Most recent observation date

Estimated Diameter

Best guess based on shape and light reflection intensity

Orbit & Impact Data
Impact Year Range

Years in which impact could occur

Potential Impacts

Possible impacts throughout year range

Impact Probability

Cumulative chance across all passes

Velocity (V∞)

Speed without major gravitational pull

Reference Scales
Palermo Scale

Logarithmic · Technical Audience

< -2 -2 -1 0 > 0
< -2 Less than 1% of background risk Minimal concern
-2 to -1 1-10% of background risk Worth monitoring
-1 to 0 10-100% of background risk Careful attention
0 Equal to background risk Serious attention
> 0 Exceeds all background risk High priority

Reported as Cumulative (all passes) and Maximum (worst single pass). Nothing currently exceeds -2.

Torino Scale

Integer 0-10 · Public Communication · Impacts < 100 Years Away

0 1 2 3 4 5 6 7 8 9 10
0 No Hazard Burns up in atmosphere or no risk
1 Normal Routine pass, no discernible danger
2-4 Attention Warrants monitoring by astronomers
5-7 Threatening Potentially unprecedented global threat
8-10 Certain Collision certain; size determines severity

No known object currently exceeds a Torino score of 1.