Don't Look Up!

Earth safe from 'city-killer' asteroid 2024 YR4!

Hey, Space Fans!

Happy Monday and we're starting off the week with a big (think huge space rock wize) weight off our minds as astronomers just dramatically reduced the potential threat risk of the newfound asteroid 2024 YR4 down to miniscule odds. The asteroid briefly set a record for the highest threat level ever, at a 1-in-32 chance of hitting Earth in 2032.

"The NASA JPL Center for Near-Earth Object Studies (CNEOS) now lists the 2024 YR4 impact probability as 0.00005 (0.005%) or 1-in-20,000 for its passage by Earth in 2032," Richard Binzel, Professor of Planetary Science at the Massachusetts Institute of Technology (MIT) and creator of the Torino scale exclusively told Space.com. "That's impact probability zero folks!"

Whew!

Don't Look Up

In the unlikely event that you haven't got enough things on your mind to worry about; here is a tidbit that crossed my news feed recently.

Asteroid 2024 YR4 was discovered on December 27 of last year and is estimated to be 196 feet wide - about the size of the Statue of Liberty and 27 million miles distant. If it were to strike planet earth there is a high probability that it could result in significant damage; likely similar to the 1908 event which flattened a vast forested area in Tunguska Siberia.

Yesterday NASA announced that this chunk of galactic rock  had an estimated 3.1% chance of impacting earth on December 22, 2032 - a 1 in 42 chance of collision.

It is useful to note that the probability of an impact can change as additional data is collected.  Asteroid 99942 Apophis was initially considered at high risk of colliding with earth; and with continued monitoring these worries were ruled out. 

NASA and other space agencies are actively monitoring 2024 YR4 as the asteroid is currently rated as a 3 on the Torino Impact Hazard Scale ranking this as a close-enough encounter with a 1% or greater chance of impact capable of causing localized destruction.  Who knew?  As events unfold the asteroid's trajectory and probability of impact will be updated.

If the impact probability remains significant there are further options.  NASA could attempt to deflect the object by means of altering its trajectory.  NASA mounted a successful DART mission in 2022 to test the feasibility of this as a defense strategy. 

With a 3.1% probability of an impact this is worth paying attention.  Of course there is a much higher probability that Elon Musk will dismantle and defund NASA, furlough all of the agency's slothful and ungrateful workers, disappear the NASA.gov website, strike the name from all of the empty buildings and for good measure supplant it with his own company.

In which case I recommend you interview a contractor who can construct for you a sturdy bunker.  

You can learn more about the science of tracking a predicting all of these near-earth objects that keep you up at night. 

Don't Look Up

On this day in history thirteen years ago a meteor entered the atmosphere above Chelyabinsk Oblast in the southern Ural region of Russia.  It exploded with the force estimated to be more than thirty times that of the nuclear device used on Hiroshima.  

Likely originating from the asteroid belt located between Mars and Jupiter it was estimated to be approximately 60 feet in diameter and 9100 tons.  Its approach to earth was a shallow trajectory with an estimated speed of 43,000 miles per hour.  The blinding light was visible up to 60 miles distant and exploded in an air burst at an altitude of about 18 miles (97,000 feet).  Remarkably, nobody saw it coming as its radiant (direction of approach) was from the sun.  

Even more remarkable, there were no deaths; although, almost 1,500 individuals sought medical treatment for injuries mostly from indirect injuries (broken glass) as a consequence of the shock waves from the blast.  7,200 buildings in six cities across the region were damaged. 

In the aftermath of the air burst a significant number of small meteorites fell in areas west of Chelyabinsk; described as gravel falling from the sky. In 2013 Russian scientists identified a two foot sized chunk buried in the muddy bottom of Lake Chebarkul.  It was recovered, broke the scales used to weigh it and split into three pieces.  

This meteor event is the largest known object to have entered the atmosphere since the Tunguska event in 1908 which destroyed a large forested area in a remote part of Siberia. 

August Night Sky

In keeping with the smorgasbord of celestial events that the month of August has had to offer I would like to introduce you to something new.  A protoplanet.

A protoplanet (Word of the Day) is basically a dwarf or normal planet in the making.  The difference is that it lacks the spherical shape of the heavenly bodies we understand to be planets as a consequence of insufficient gravity relative to their smaller mass.

I bring this subject-up because I posted a sky map a few days ago pertaining to Saturn's opposition.  The map included an object visible to the naked eye named Vesta.  Vesta is the last known protoplanet in our solar system. 

Vesta is the second most massive body in the asteroid belt surpassed only by Ceres which happens to be classified as a dwarf planet.  One of the brightest objects in the sky Vesta is visible to a determined observer from time to time.  It also happens to be the first of the four largest asteroids - Ceres, Vesta, Pallas and Hygiea) to have been explored by unmanned spacecraft.  The Dawn mission orbited Vesta in 2012 and discovered new insights into this big rock.

Discovered by the German astronomer Heinrich Wilhelm Matthias Olbers in 1807 it is named for Vesta - the virgin goddess of hearth and home in Roman mythology.

This image of the asteroid was taken by NASA's Dawn spacecraft and the numerous impact craters are evidence of a violent life.

Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Unlike its asteroid neighbors the interior of Vesta is different.  As with other terrestrial planets it has a crust of cooled lava covering a rocky mantle and a nickle and iron core.  It is for these reasons it is classified as a protoplanet instead of an asteroid.

In any event, I shared that this object is sometimes viewed by means of the naked eye.  In the early morning hours of August 22 Vesta will be in opposition and its 326 mile-wide reflective surface may be highly visible under a waning crescent moon.  These are good viewing conditions.

If you get-up to pee in the wee hours take moment to look for this Roman virgin in the southern night sky.  If you require reading material you can learn more about Vesta via Space.com.

Locator map...

Stellarium