Dee Finney's blog
start date July 20, 2011
today's date January 2, 2014
TOPIC: PREVENTING ASTEROIDS FROM HITTING EARTH
NOTE: MULTIPLE METEOROIDS AND METERORITES HAVE BEEN
GOING THROUGH EARTH'S ATMOSPHERE RECENTLY. NO REPORTS OF STRIKES TO EARTH,
BUT THAT DOESN'T MEAN THAT DUST FROM THESE OBJECTS IS NOT FALLING DOWN UNNOTICED
THAT COULD HAVE BACTERIA ON THEM THAT HUMANITY WOULDNT KNOW WHAT TO DEAL WITH IF
IT WAS BREATHED IN. THE BIGGER DANGER AT THIS POINT - IS - WITH SO MANY
ASTEROIDS GOING AROUND EARTH AT ANY ONE MOMENT, WHERE ARE THEY ALL AND HOW CAN
WE PREVENT THEM FROM STRIKING EARTH?
I HAVE PREVIOUSLY WRITTEN ON THIS TOPIC 242 TIMES AND
TRACKED ASTEROIDS FOR A THREE YEAR PERIOD RIGHT AFTER OUR DEAR FRIEND KENT
STEADMAN SUDDENLY PASSED AWAY IN 2008. WE DECIDED TO RESUME THESE REPORTS IN
2014 BECAUSE THERE IS NEW EFFORT TO TRACKING AND PREVENTING ASTEROIDS FROM
STRIKING EARTH WHICH WOULD BE DISASTROUS - MORE SO IF ONE WAS VERY LARGE.
IN 2010, I PUBLISHED THIS LIST:
On January 17, there were 1092 potentially
On February 17, there were 1100 potentially hazardous asteroids.
NOTE: These are not 'new' asteroids' merely newly discovered by
people and their new telescopes.
On March 24, there were 1110 potentially hazardous asteroids.
On April 5, there are 1110 potentially hazardous asteroids.
On April 14, there are 1117 potentially hazardous asteroids.
On May 15, there are 1127 potentionally
On June 19, there are 1133 potentially hazardous asteroids.
On June 23, there are 1138 potentially hazardous asteroids.
On July 23, there are 1140 potentially hazardous asteroids.
THIS IS TODAY'S LIST
Potentially Hazardous Asteroids (PHAs)
are space rocks larger than approximately 100m that can come closer to Earth
than 0.05 AU. None of the known PHAs is on a collision course with our planet,
although astronomers are finding new
On January 2, 2014 there were 1448 potentially
Recent & Upcoming Earth-asteroid encounters:
means "Lunar Distance." 1 LD = 384,401 km, the distance between Earth and the
Moon. 1 LD also equals 0.00256 AU.
MAG is the visual magnitude of the asteroid on the date of
As you can clearly see, the number of sighted asteroids
is growing because more and more amateur astronomers are diligently daily
searching the skies over our head all over the earth.
Recently Reactivated NASA Spacecraft Spots Its First New Asteroid
The six red dots in this composite picture indicate the location of
the first new near-Earth asteroid seen by NASA's Near-Earth Object
Wide-field Infrared Survey Explorer (NEOWISE).
NASA's Near-Earth Object Wide-field Infrared Survey
Explorer (NEOWISE) spacecraft has spotted a
never-before-seen asteroid -- its first such discovery since
coming out of hibernation last year.
NEOWISE originally was called the Wide-field Infrared Survey
Explorer (WISE), which had made the most comprehensive
survey to date of asteroids and comets. The spacecraft was
shut down in 2011 after its primary mission was completed.
But in September 2013, it was reactivated, renamed and given
a new mission, which is to assist NASA's efforts to identify
the population of potentially hazardous near-Earth objects
(NEOs). NEOWISE also can assist in characterizing previously
detected asteroids that could be considered potential
targets for future exploration missions.
NEOWISE's first discovery of its renewed mission came on
Dec. 29 -- a near-Earth asteroid designated 2013 YP139. The
mission's sophisticated software picked out the moving
object against a background of stationary stars. As NEOWISE
circled Earth scanning the sky, it observed the asteroid
several times over half a day before the object moved beyond
its view. Researchers at the University of Arizona used the
Spacewatch telescope at the Kitt Peak National Observatory
southwest of Tucson to confirm the discovery. Peter
Birtwhistle, an amateur astronomer at the Great Shefford
Observatory in West Berkshire, England, also contributed
follow-up observations. NASA expects 2013 YP139 will be the
first of hundreds of asteroid discoveries for NEOWISE.
"We are delighted to get back to finding and characterizing
asteroids and comets, especially those that come into
Earth’s neighborhood," said Amy Mainzer, the mission's
principal investigator from NASA's Jet Propulsion Laboratory
(JPL) in Pasadena, Calif. "With our infrared sensors that
detect heat, we can learn about their sizes and
2013 YP139 is about 27 million miles (43 million kilometers)
from Earth. Based on its infrared brightness, scientists
estimate it to be roughly 0.4 miles (650 meters) in diameter
and extremely dark, like a piece of coal. The asteroid
circles the sun in an elliptical orbit tilted to the plane
of our solar system and is classified as potentially
hazardous. It is possible for its orbit to bring it as close
as 300,000 miles from Earth, a little more than the distance
to the moon. However, it will not come that close within the
WISE discovered more than 34,000 asteroids and characterized
158,000 throughout the solar system during its prime mission
in 2010 and early 2011. Its reactivation in September
followed 31 months in hibernation.
NEOWISE will continue to detect asteroids and comets. The
observations will be automatically sent to the clearinghouse
for solar system bodies, the Minor Planet Center in
Cambridge, Mass., for comparison against the known catalog
of solar system objects and to determine orbit if the object
is not known. A community of professional and amateur
astronomers will provide follow-up observations,
establishing firm orbits for the previously unseen objects.
Infrared sensors, similar to the cameras on NEOWISE, are a
powerful tool for discovering, cataloging and understanding
the asteroid population. Some of the objects about which
NEOWISE will be collecting data could become candidates for
NASA's announced asteroid initiative, which will be the
first mission to identify, capture and relocate an asteroid
for astronauts to explore. The initiative represents an
unprecedented technological feat that will lead to new
scientific discoveries and technological capabilities that
will help protect our home planet and achieve the goal of
sending humans to an asteroid by 2025.
JPL manages the project for NASA's Science Mission
Directorate in Washington. The Space Dynamics Laboratory in
Logan, Utah, built the science instrument. Ball Aerospace &
Technologies Corp. of Boulder, Colo., built the spacecraft.
Science operations and data processing take place at the
Infrared Processing and Analysis Center at the California
Institute of Technology in Pasadena. Caltech manages JPL for
An image of asteroid 2013 YP139, taken by NEOWISE, is
More information about NEOWISE is available online at:
Jet Propulsion Laboratory, Pasadena, Calif.
Asteroids are minor
planets, especially those of the inner
Solar System. The larger ones have also been called planetoids.
These terms have historically been applied to any astronomical object orbiting
that did not show the disk of a planet and was not observed to have the
characteristics of an active comet, but as minor planets in the outer
Solar System were discovered,
surfaces were found to resemble comets more closely and so were often
distinguished from traditional asteroids. Thus
the termasteroid has come
increasingly to refer specifically to the small bodies of the inner Solar System
out to the orbit of Jupiter.
They are grouped with the outer bodies—centaurs, Neptune
trojans, and trans-Neptunian
objects—as minor planets, which is the term preferred in astronomical
this article the term "asteroid" refers to the minor planets of the inner Solar
There are millions of asteroids, many thought to be the shattered remnants of planetesimals,
bodies within the young Sun's solar
nebula that never grew large
enough to become planets. The
large majority of known asteroids orbit in the asteroid
belt between the orbits of Mars
and Jupiter, or are co-orbital with Jupiter (the Jupiter
Trojans). However, other orbital families exist with significant
populations, including the near-Earth
asteroids. Individual asteroids are classified by their characteristic spectra,
with the majority falling into three main groups: C-type, S-type,
These were named after and are generally identified with carbon-rich, stony,
and metallic compositions,
Only one asteroid, 4
Vesta, which has a relatively reflective surface, is normally visible to the
naked eye, and this only in very dark skies when it is favorably positioned.
Rarely, small asteroids passing close to Earth may be visible to the naked eye
for a short time. As
of September 2013, the Minor Planet Center had data on more than one million
objects in the inner and outer Solar System, of which 625,000 had enough
information to be given numbered designations.
HERE IS A NASA GRAPHIC FROM EARLY 2013 OF POTENTIALLY HAZARDOUS ASTEROIDS IN
YOU CAN SEE HOW MANY COULD INTERSECT THE ORBIT OF
EARTH AT SOME GIVEN POINT.
HERE IS THE ORBIT OF 2013 YL2 WHICH IS CLOSEST TO EARTH
ON JANUARY 3, 2014
THAT IS THE CLOSEST ONE IN THE FIRST QUARTER OF THIS
http://www.spaceweather.com for the daily update of asteroid threats to
Discovered on New Year's Eve by a telescope
in Arizona, a small asteroid struck Earth somewhere over the Atlantic
Ocean — apparently unnoticed — about 25 hours later.
It was New Year's Eve, but that didn't stop observer Richard Kowalski
from scanning the sky for near-Earth objects (NEOs). He hadn't been
using the 60-inch telescope on Arizona's Mount Lemmon for long when he
noticed a 19th-magnitude blip skimming through northern Orion in a
seven-image series begun at 5:16 p.m. (1:16 Universal Time on January
1st). After confirming that it was a new find, Kowalski dutifully
submitted positions and times to the IAU's Minor Planet Center. Then he
went back to the night's observing run.
This plot shows the range of possible locations where the
small asteroid 2014 AA struck Earth's atmosphere early on
January 2, 2014.
Bill Gray / Project Pluto
Thus did the Mount Lemmon reflector, part of the Catalina
, discover 2014 AA, the first asteroid found this year.
But at the time neither Kowalski nor anyone else realized that the
little intruder was only 300,000 miles (500,000 km) from Earth and
by the MPC
it's "virtually certain" that 2014 AA hit Earth. According to
calculations by dynamicist Stephen Chesley (Jet Propulsion
Laboratory), the impact occurred over the Atlantic Ocean somewhere
between Central America to East Africa. Chesley's "best-fit" collision
is just off the coast of West Africa at roughly 2:30 Universal Time this
More precision has come from an analysis of infrasound data by Peter
Brown (University of Western Ontario). Infrasound is extremely
low-frequency acoustic energy (20 hertz or less) created, for example,
during energetic explosions. A global
network of detectors
, maintained by the Comprehensive
Nuclear-Test-Ban Treaty Organization, can pinpoint the location and
energy of any powerful detonation — including airbursts from meteoric
The overlap of the white curves, from three marginal
infrasound detections, shows where the small asteroid 2014
AA likely hit. However, this preliminary plot does not take
winds into account, which might shift the true impact point
somewhat further east.
According to Brown, 2014 AA triggered very weak detections at three
infrasound stations. His triangulation from those records, shown in the
graphic at right, indicates that the space rock slammed into the
atmosphere near 40° west, 12° north. That location, about 1,900 miles
(3,000 km) east of Caracas, Venezuela, is far from any landmass.
"The energy is very hard to estimate with much accuracy — the signals
are all weak and buried in noise," Brown explains. And yet, he adds,
we're lucky that the event happened just after local midnight, when
winds are calmest. "Had this occurred in
the middle of the day I doubt we would see any signals at all," he says.
Brown's rough guess is that the impact energy was equivalent to the
explosive power of 500 to 1,000 tons of TNT — which, though powerful in
human terms, implies the object was no bigger than a small car. "It was
So 2014 AA was too small to reach the ground intact. But it must have
created one heck of a fireball! The skies over the Atlantic were
relatively clear last night. Alas, a search of ship- and plane-tracking
websites turned up no vessels in that area — it seems that no one was
positioned to witness 2014 AA's demise.
"I'm not aware of any visual sightings," says William Cooke of NASA's
Meteoroid Environment Office in Huntsville, Alabama. "Looks like it was
too far away from human eyes."
The impact occurred a little after 3h
Brown says. That's only about 22 hours after Kowalski's initial report
to the MPC, and it's giving me déjà vu all over again. It's been just
five years since another small asteroid called 2008
TC3 struck Earth
just 19 hours
after its discovery by the same telescope.
The difference between these events is that astronomers had nearly a day
of advance warning regarding the 2008 impact. Telescopes worldwide
amassed hundreds of observations before the object slammed into the
atmosphere, and eventually many
fragments were recovered
Based on images taken in the hours before its impact,
asteroid 2014 AA averaged 110 million miles (175 million km)
from the Sun in a low-inclination orbit that crossed paths
with Mars and Earth. It was only a matter of time before it
encountered our planet. Click on the image for an
There was no heads-up alert this time. "I'm kicking myself for not
having spotted this," admits amateur NEO sleuth Bill Gray (Project
). Most mornings Gray downloads "and yes, for me, it was
Most mornings, he downloads the circumstances for recent discoveries and
computes "what ifs" for potential impactors and near-misses. "However,
on New Year's Day, I'd made arrangements to go with my family to visit
my sister, go for a walk, stop off for a doughnut, shovel snow, etc.,
etc." He didn't realize an impact was imminent until last night — only a
couple of hours before the impact.
Let's cut Gray some slack and instead give him, Chesley, and Gareth
Williams at the MPC a collective pat on the back. All three were able to
conclude — based on just seven images taken
within 3 minutes
only that 2014 AA was going to strike Earth, but also roughly where and
when. Mad props for that impressive number-crunching!
THIS IS WHERE I POST WHAT I'M DOING AND THINKING
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