Physical Constraints Paper

STAMP: 2 Cleared For Open Publication Mar 08, 2023

Draft Version March 1, 2023 Typeset using LaTeX default style in AASTeX631

Department of Defense Office of Prepublication and Security Review

Physical Constraints on Unidentified Aerial Phenomena

Abraham (Avi) Loeb1 and Sean M. Kirkpatrick2

1 Head of the Galileo Project, Astronomy Department, Harvard University 60 Garden Street, Cambridge, MA 02138, USA 2 All-domain Anomaly Resolution Office 1010 Defense Pentagon Washington DC 20301, USA

Abstract

We derive physical constraints on interpretations of "highly maneuverable" Unidentified Aerial Phenomena (UAP) based on standard physics and known forms of matter and radiation. In particular, we show that the friction of UAP with the surrounding air or water is expected to generate a bright optical fireball, ionization shell and tail - implying radio signatures. The fireball luminosity scales with inferred distance to the 5th power. Radar cross section scales similarly to meteor head echoes as the square of the effective radius of the sphere surrounding the object, while the radar cross section of the resulting ionization tail scales linearly with the radius of the ionization cylinder. The lack of all these signatures could imply inaccurate distance measurements (and hence derived velocity) for single site sensors without a range gate capability.

Keywords: Interstellar objects – Meteors – meteoroids – Meteorites – Bolides – asteroids: general – asteroids: individual (A/2017 U1) – Minor planets – Oumuamua

Introduction

In 2005, the US Congress tasked NASA to find 90% of all Near Earth Objects (NEOs) that are larger than 140 meters [Loff 2014]. The Congressional task resulted in the construction of the Pan-STARRS telescopes. On October 19, 2017, the Pan-STARRS sky survey flagged an…