PHA meaning in Academic & Science ?

Answer: What is Potentially Hazardous Asteroid mean?

A potentially hazardous object (PHO) is a near-Earth object – either an asteroid or a comet – with an orbit that can make close approaches to the Earth and is large enough to cause significant regional damage in the event of impact. They are defined as having a minimum orbital intersection distance with Earth of less than 0.05 astronomical units (19.5 lunar distances) and an absolute magnitude of 22 or brighter. 99% of the known potentially hazardous objects are not an impact threat over the next 100 years. Only about 19 potentially hazardous objects are listed on the Sentry Risk Table as objects that are known not to be a threat over the next hundred years are excluded. Over hundreds if not thousands of years, "potentially hazardous" asteroids have the potential for their orbits to evolve to live up to their namesake.

Most of these objects are potentially hazardous asteroids (PHAs), and a few are comets. As of August 2021 there are 2,203 known PHAs (about 8% of the total near-Earth population), of which 159 are estimated to be larger than one kilometer in diameter (see list of largest PHAs below). Most of the discovered PHAs are Apollo asteroids (1,730) and fewer belong to the group of Aten asteroids (171).

A potentially hazardous object can be known not to be a threat to Earth for the next 100 years or more, if its orbit is reasonably well determined. Potentially hazardous asteroids with some threat of impacting Earth in the next 100 years are listed on the Sentry Risk Table. As of August 2021, only about 19 potentially hazardous asteroids are listed on the Sentry Risk Table. Most potentially hazardous asteroids are ruled out as hazardous to at least several hundreds of years when their competing best orbit models are sufficiently constrained, but recent discoveries whose orbital constraints are little-known have divergent or incomplete mechanical models until observation yields further data. After several astronomical surveys, the number of known PHAs has increased tenfold since the end of the 1990s (see bar charts below). The Minor Planet Center's website List of the Potentially Hazardous Asteroids also publishes detailed information for these objects.

In May 2021, NASA astronomers reported that 5 to 10 years of preparation may be needed to avoid a potential impactor based on a simulated exercise conducted by the 2021 Planetary Defense Conference.

reference

Full Form	Category
Poly Hyrdroxy Acid	Academic & Science
Pharyngealization	Academic & Science
Prince Hall Affiliated	Academic & Science
Potentially Hazardous Asteroid	Academic & Science
Prospect Hill Academy	Academic & Science
Phan Rang	Airport Code
Public Holdings (Australia) Ltd	Business
Process Hazard Analysis	Business
Pharmacia Corporation	Business
Packowski Heinritz Associates	Business
Pennsylvania Homecare Association	Community
Prince Hall Association	Community
Peoria Housing Authority	Community
Public Housing Authorities	Community
Parks and Horticulture Authority	Community
People Having AIDS	Community
Public Housing Agencies	Community
Pacific Health Association	Community
Pearl Harbor Associates	Community
Pulmonary Hypertension Association	Community
Professional Horsemen's Association	Community
Phala Network	Cryptocurrency
Pulse Height Analysis	Electronics
Prince Hall Affiliate	General
Peripheral Hear Action	General
Progressive Hammer Action	General
Premium High Availability	General
Plan for a Healthier Allegheny	General
Produce Handling Assurance	General
Potentially Harmful Applications	General
Pyeong Hwa Automotive	General
Phaeton	General
Provincial Highway Administration	General
Poly- Hydroxy Alkanoate	General
Partnership For A Healthier America	General
Port of Houston Authority	Governmental
Public Health Advisory	Governmental
Public Health Advisor	Governmental
Public Health Assessment	Governmental
Pakistan Housing Authority	Governmental
Portland Housing Authority	Governmental
Physician Hospital Alliance	Governmental
Portsmouth Housing Authority	Governmental
Public Housing Agency	Governmental
PATHARIA	Indian Railway Station
Perfectly Hopeless A**	Internet
Pediatric Healthcare Associates	Medical
Periodic Health Assessment	Medical
Purdue Healthcare Advisors	Medical
Population Health Alliance	Medical
Passive Haemagglutination Assay	Medical
Pelger-Hüet anomaly	Medical
Personal Health Assessment	Medical
phytohaemagglutinin	Medical
Posterior Hypothalamic Area	Medical
posthypnotic amnesia	Medical
primary hyperaldosteronism	Medical
pseudohypoaldosteronism	Medical
Public Health Agency	Medical
Public Health Alliance (incorporated into UKPHA)	Medical
Public Health Association	Medical
Pulse-Height Analyser	Medical
Post-development Health Assessment	Medical
Physician Hospitals Of America	Medical
Personal Health Applications	Medical
Preventive Health Assistance	Medical
Periodic Health Assessments	Medical
Public Health Action	Medical
Public Health Assessments	Medical
Preventive Health Assessment	Medical
Peripheral Heart Action	Medical
Preliminary Hazard Analysis	Military and Defence
Physical Health Assessment	Military and Defence
Public Housing Authority	Real Estate
Providence Housing Authority	Real Estate
Piedmont Housing Alliance	Real Estate
Philadelphia Housing Authority	Real Estate
Plant Health Australia	Regional
Phan Rang, Vietnam	Regional
Preliminary Hazard Analyses	Space Science
Pulse Height Analyzer	Space Science
Potentially Hazardous Asteroids	Space Science
Prowler Hockey Assoc	Sports
Pacific Hockey Association	Sports
Peterborough Hockey Association	Sports
Palomino Horse Association	Sports