Evidence · Incident 88: the Hackensack disc, 3 August 1947

The reported course is 41 degrees left of downwind, and a small near balloon matches the reported size and speed

At 7 and 8 pm Teterboro's wind was from 225 degrees at 2.6 m/s under a clear sky; the course Casella described, Bendix to west of Westwood, bears 4 degrees, 41 degrees left of the downwind direction of 45 degrees; a 0.3 m balloon at 60 m gives the same angular size, about 0.3 degrees, as the witnesses' 30-40 inches at 200 yards, and would cross the sky at about 3.8 degrees a second.

Suggestive0

What it means

Key questionWhat did the three witnesses see over Hackensack on the evening of 3 August 1947?

3 answers, none ahead yet

Openunchanged

Part of itDo the object's reported course, size and motion fit a small balloon drifting on that evening's wind?

2 answers, none ahead yet

Openwas No evidence yet

Answer this evidence bears onYes: within the error of a course rebuilt from landmarks days later

Supports1 for, none against

Still possiblewas No evidence yet

What it implies

The course gap is real but inside the error of a landmark course and of wind turning with height; size and motion fit a nearby balloon.For: Do the object's reported course, size and motion fit a small balloon drifting on that evening's wind?
A small balloon remains a workable explanation; the sighting needs no unknown object.For the key question: What did the three witnesses see over Hackensack on the evening of 3 August 1947?

Next steps 3

Find the evening pilot-balloon winds for Newark or LaGuardia, 4 Aug 1947 00Z

Could decideFair odds~4 h

On: Do the object's reported course, size and motion fit a small balloon drifting on that evening's wind?Set by this evidence

35score

Details

Look for 1947 upper-air (pibal) winds in NOAA IGRA or the Weather Bureau's printed winds-aloft records. Wind near 200-300 m from the south or south-south-west would close the 41-degree gap and support a balloon; wind from west or north-west would rule out free drift.

Find the evening pilot-balloon winds for Newark or LaGuardia, 4 Aug 1947 00Z

Could decideFair odds~4 h

On: Do the object's reported course, size and motion fit a small balloon drifting on that evening's wind?

35score

Details

Wind near 200-300 m from the south or south-south-west closes the gap; from west or north-west it rules out free drift.

Winds aloft for 4 Aug 1947 00Z

Could decideFair odds~4 h

On: Do the object's reported course, size and motion fit a small balloon drifting on that evening's wind?

35score

Details

Find Newark or LaGuardia pilot-balloon winds near 200-300 m for the evening of 3 August 1947; south or south-south-west closes the course gap, west or north-west rules out free drift.

Ranked by how likely each is to move the key question, for the time it takes

How it was found 1 run

Teterboro wind, sun and size check for the Hackensack object

Method Wind-drift and angular-size check for a low sighting · Session 1

Result. The wind at 7 and 8 pm was from the south-west at 2.6 m/s under a clear sky, and the reported northward course lies 41 degrees left of downwind; a 0.3 m balloon at 60 m matches the reported angular size and would cross the sky three times faster than the witnesses' own size-distance estimate implies.

Test · estimate [95% interval]Against the null and the answersVerdict

Reported course minus downwind direction, 3 Aug 1947 eveningdegrees

−41.4

One course reconstructed from landmarks by one witness; no error was recorded, so no interval can be computed.

Needs an interval

Estimate, 68% interval (thick) and 95% (thin). Rule declared with the run: Set before the run: rule out free drift if the course lies more than 60 degrees from downwind.

Figure 1

The wind settled into a light south-westerly before the sighting and held through it

Teterboro Airport hourly wind speed, 3 August 1947, local time (EDT); direction 180-225 degrees throughout

wind speed

The sighting fell between the 19:00 and 20:00 observations (highlighted); sky clear, visibility 14 km. Sunset 20:15 EDT. Wind measured near the ground; the wind 200 m up was not recorded here.

Drawn by the site with Teterboro wind, sun and size check for the Hackensack object

Figure 2

A small balloon 60 m away looks the size the witnesses described and crosses the sky three times faster

Angular size and drift rate in a 3.9 m/s wind for the witnesses' estimates and for a 0.3 m balloon

angular size (deg)drift rate (deg/s)

Wind at 183 m scaled from 2.6 m/s at 10 m by a 1/7 power law. The witnesses' size and distance cannot both be checked; equal angular size is what they actually saw.

Drawn by the site with Teterboro wind, sun and size check for the Hackensack object

Teterboro Airport hourly surface observations, 1947 (NOAA ISD 99999994741)hackensack_check.py 3 outputs

Sources 2

Global Hourly – Integrated Surface Database: Teterboro Airport, NJ (station 99999994741), 1947

Information 1947

SRC

SAC Newark to Director, FBI: Flying disc reported at Hackensack, New Jersey, August 3, 1947 – Miscellaneous (FBI file 62-HQ-83894, Section 2)

Federal Bureau of Investigation 1947

SRC

Cite it

Mysteries Department. (2026). The reported course is 41 degrees left of downwind, and a small near balloon matches the reported size and speed [Evidence EVD0DFY8Y0RC6PS]. https://mysteriesdept.com/r/EVD0DFY8Y0RC6PS

@misc{mysteriesdept_evd0dfy8y0rc6ps,
  title     = {The reported course is 41 degrees left of downwind, and a small near balloon matches the reported size and speed},
  author    = {{Mysteries Department}},
  year      = {2026},
  note      = {Evidence, catalog key EVD0DFY8Y0RC6PS},
  url       = {https://mysteriesdept.com/r/EVD0DFY8Y0RC6PS}
}