THE SOUTHWORTH PLANETARIUM
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70 Falmouth Street   Portland, Maine 04103
43.6667° N                   70.2667° W
Altitude:  10 feet below sea level
Founded January 1970
Julian date: 2458737.5
2019-2020:  VII
             "I didn't actually say most of the things I said."
                                 -Yogi Berra


THE DAILY ASTRONOMER
Wednesday, September 11, 2019
Three Hurtling Asteroids

veered precariously close to Earth the other day!   Although these three
tumbling outer space mountains might have wreaked some havoc had they hit
the surface, they instead careened tip over teakettle into the soundless
voids of interplanetary space.  Predictably, the media over-hyped the
events to make us jerk our heads up and take notice.  However, they needn't
have mentioned the matter: we were never imperiled.

The three potentially problematic projectiles were, in alphabetical order

2019 QY4
2019 QZ3
and
2019 RG2

2019 QZ3 was -and likely still is- the largest of the trio with a 220-foot
diameter, slightly smaller than the length of a football field. 2019 RG2
spanned merely 66 feet; teeny 2019 QY4 just 52 feet.   As slight as these
three rocks might seem relative to the much more massive inner planets,
they all still posed a danger due to their rapid speeds. RG2, the hare of
the triumvirate, is speeding along at 50,000 miles per hour.  Though
comparatively lethargic, QY4 and QZ3 are still zooming along at 17,000 and
16,700 miles per hour, respectively.   At those velocities, the asteroids
could have inflicted substantial damage to the localities around which any
impact would have occurred.  They wouldn't, however, have laid waste to
civilization owing to their minuscule size.  (The asteroid that hastened
the end of the Cretaceous period and destroyed 90% of all species then
extant, including the non-avian dinosaurs, measured 10 miles in diameter.)

[image: TkApf7uR5qQA6LNatzrtWF.jpg]
A horrifying graphic showing the location of all the Near Earth objects
known as of January 2018.    However, the image is deceptive as these
asteroids are dispersed through a vast sphere of interplanetary space.

QY4, QZ3 and RG2 are just three examples of the 878 Near Earth Objects
(NEO's) that might post a risk to our planet at some point.   Even these
bodies likely represent just a portion of all the potentially hazard
asteroids (PHA's) that likely remain hidden within the dark expanses of
interplanetary space.  Although our neighborhood is much safer than it was
during the late heavy bombardment -if that actually happened-, our region
of space is still fraught with peril.  In fact, other powerful asteroid
impacts are inevitable, just not imminent, or so astronomers believe.
 This latest three-asteroid fly-by serves as another disquieting reminder
that even in our relatively quiescent five billion year old solar system,
dangers still lurk in the darkness.


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