UPDATE (7 a.m. ET): Discoverer Anthony Wesley has released his own video of the Jovian fireball (.avi, 45Mb).
(.avi, 45Mb). Looking at the flash, it is obviously a large object (after all, this is Jupiter we’re looking at!), but there doesn’t appear to be any associated plume or scarring on the upper atmosphere. Although it’s difficult to draw any conclusions from this — we need to wait for some expert analysis — it could be that this impactor was made of softer ‘stuff’ than the 2009 suspected asteroid. Thursday’s fireball could have been an icy comet or loosely-packed asteroid (i.e. a “rubble pile”) burning high in the atmosphere rather than penetrating very deep (h/t Bad Astronomy ).
Serendipity is often a key player in astronomical observations, and it looks like Australian amateur astronomer Anthony Wesley was looking in the right place at the right time to see an impact on Jupiter, again .
You might remember Wesley from last year when he was the first to observe a massive impact event in Jupiter’s atmospherewhen, at the time, it was believed a comet had struck the gas giant, leaving behind a ‘bruise’ the size of the Pacific Ocean.
This morning, Hubble released more informationabout the famous July 19, 2009 event revealing the results of a study surrounding the impact site. Using Hubble’s Wide Field Camera 3 and newly repaired Advanced Camera for Surveys, researchers analyzed the 2009 impact showing there was less dust than expected surrounding the comet impact site.
Also, by calculating the impactor’s trajectory, researchers have worked out that the object probably didn’t have the same orbital characteristics of a comet. After all, we’ve seen comet impacts on Jupiter before — the July 1994 impact of Shoemaker-Levy 9— so the scientists using the Hubble data had something to compare the 2009 impact with.
In all likelihood, this means that the impactor wasn’t a comet at all, but an asteroid. This is an unprecedented finding, never before has the immediate aftermath of an asteroid strike been observed.
As if that wasn’t amazing enough, on the same day the new Hubble findings were announced, Wesley has done it again: he witnessed another impact in Jupiter’s atmosphere at 20:30 UTC (3:30 pm EST).
As reported by Bad Astronomer Phil Plait, Wesley’s observation has been confirmed by a second amateur astronomer Christopher Go.
Go has also posted a video of the event(via SpaceWeather.com) A single frame of the fireball (which lasted 2 seconds) is posted at the top of the page.
From the Australian Amateur Astronomer website, Ice In Space, where the announcement was made:
“ …at approximately 20:30utc this morning I recorded a large fireball on Jupiter, it lasted a couple of seconds and was very bright. This was a large fireball, but it doesn’t seem to have left any mark, probably all gone in the upper atmosphere before it reached the clouds. “ –Anthony Wesley.
I am stunned that Wesley hasn’t only observed two of these events (seeing one such event is a once-in-a-lifetime ‘thing’), but he also happened to be observing on the exact same day Hubble releases new analysis of a possible asteroid — and not a comet — strike as being the culprit for Jupiter’s bruise in 2009!
Add these serendipitous events with the fact the 2009 impact occurred 15 years to the week after the Shoemaker-Levy 9 comet plunge in July 1994.
So, Jupiter took another one for the team, ultimately keeping comets and asteroids from diving into the inner solar system, helping life on Earth evolve without too many impact events to ruin our day.
Thank you Jupiter, and congratulations Anthony Wesley for spotting your second ‘once-in-a-lifetime’ event less than a year after your first.
Source: Bad Astronomy , SpaceWeather.com