Extra-solar fireballs??

The cosmos at our fingertips.
User avatar
JohnD
Tea Time, Guv! Cheerio!
Posts: 1042
Joined: Wed Feb 16, 2005 2:11 pm
Location: Lancaster, England

Extra-solar fireballs??

Post by JohnD » Wed Jun 13, 2018 9:23 pm

Today, 13th June, the Space Weather site features the NASAAll-Sky Fireball Network: http://spaceweather.com/
It shows a graphic of the calculated orbits of objects that have penetrated the Earth's atmosphere and burned up.
Some (coded red & Yellow) are obviously heliocentric.
The really fast ones (blue & Green) appear to have 'fallen' straight down to Earth from extrasolar space.

Now, either the Earth attracts extrasolar objects, or there is a hail of them falling throuhg the Solaar System. that we don't see until they collide with us. Oumuamua was billed as the first observed extrasolar object, so are these apparantly extrasolar origins due to weaknesses in obseervation and calculation?

John

User avatar
Chris Peterson
Abominable Snowman
Posts: 13805
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: Extra-solar fireballs??

Post by Chris Peterson » Thu Jun 14, 2018 4:01 am

JohnD wrote:
Wed Jun 13, 2018 9:23 pm
Today, 13th June, the Space Weather site features the NASAAll-Sky Fireball Network: http://spaceweather.com/
It shows a graphic of the calculated orbits of objects that have penetrated the Earth's atmosphere and burned up.
Some (coded red & Yellow) are obviously heliocentric.
The really fast ones (blue & Green) appear to have 'fallen' straight down to Earth from extrasolar space.

Now, either the Earth attracts extrasolar objects, or there is a hail of them falling throuhg the Solaar System. that we don't see until they collide with us. Oumuamua was billed as the first observed extrasolar object, so are these apparantly extrasolar origins due to weaknesses in obseervation and calculation?
Millions of meteors have had their orbits calculated. To date, none have had definitively hyperbolic orbits, meaning all have parent bodies that were in closed solar orbits. No obviously extrasolar meteors have been observed.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
JohnD
Tea Time, Guv! Cheerio!
Posts: 1042
Joined: Wed Feb 16, 2005 2:11 pm
Location: Lancaster, England

Re: Extra-solar fireballs??

Post by JohnD » Thu Jun 14, 2018 7:38 am

Thanks, Chris. So their apparent extrasolar origins due to inadequate data.
John

User avatar
Chris Peterson
Abominable Snowman
Posts: 13805
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: Extra-solar fireballs??

Post by Chris Peterson » Thu Jun 14, 2018 1:48 pm

JohnD wrote:
Thu Jun 14, 2018 7:38 am
Thanks, Chris. So their apparent extrasolar origins due to inadequate data.
No, there is a rich, accurate dataset. What is it that makes you think there are apparent extrasolar origins? The color coded speed range extends from the slowest possible meteors (Earth's escape velocity, 11 km/s), to the fastest possible meteors from solar-bound objects (72 km/s). None of the meteors are observed moving faster than 72 km/s, which means they are all in solar orbit.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
neufer
Vacationer at Tralfamadore
Posts: 15051
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: Extra-solar fireballs??

Post by neufer » Thu Jun 14, 2018 3:01 pm

Chris Peterson wrote:
Thu Jun 14, 2018 1:48 pm
JohnD wrote:
Thu Jun 14, 2018 7:38 am

So their apparent extrasolar origins due to inadequate data.
No, there is a rich, accurate dataset. What is it that makes you think there are apparent extrasolar origins? The color coded speed range extends from the slowest possible meteors (Earth's escape velocity, 11 km/s), to the fastest possible meteors from solar-bound objects (72 km/s). None of the meteors are observed moving faster than 72 km/s, which means they are all in solar orbit.
The fastest possible meteors coming from head on solar-bound objects
is indeed ~72 km/s ~ sqrt[{30[sqrt(2)+1]}2+{11}2].

However, an extra-solar object can hit the Earth from behind to produce a fireball
as slow as ~17 km/s ~ sqrt[{30[sqrt(2)-1]}2+{11}2].

(Note: if this ~17 km/s extra-solar object misses the Earth it would continue off into interstellar
space much as the 16.26 km/s New Horizons was able to do with a minimal assist from Jupiter.)

Hence, the fact that no meteors are observed moving faster than 72 km/s,
is a minimum requirement that they are all in solar orbit.
Last edited by neufer on Thu Jun 14, 2018 3:18 pm, edited 1 time in total.
Art Neuendorffer

User avatar
Chris Peterson
Abominable Snowman
Posts: 13805
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: Extra-solar fireballs??

Post by Chris Peterson » Thu Jun 14, 2018 3:11 pm

neufer wrote:
Thu Jun 14, 2018 3:01 pm
Chris Peterson wrote:
Thu Jun 14, 2018 1:48 pm
JohnD wrote:
Thu Jun 14, 2018 7:38 am

So their apparent extrasolar origins due to inadequate data.
No, there is a rich, accurate dataset. What is it that makes you think there are apparent extrasolar origins? The color coded speed range extends from the slowest possible meteors (Earth's escape velocity, 11 km/s), to the fastest possible meteors from solar-bound objects (72 km/s). None of the meteors are observed moving faster than 72 km/s, which means they are all in solar orbit.
The fastest possible meteors coming from head on solar-bound objects
is indeed ~72 km/s ~ sqrt[{30[sqrt(2)+1]}2+{11}2].

However, an extra-solar object can hit the Earth from behind to produce a fireball
as slow as ~17 km/s ~ sqrt[{30[sqrt(2)-1]}2+{11}2].

Hence, the fact that no meteors are observed moving faster than 72 km/s,
is a minimum requirement that they are all in solar orbit.
Note, however, that while the color coding reflects just the vinf speed, all of these meteors have orbital elements derived. The observation that no extrasolar meteors have been detected is based on the orbit (in particular, the eccentricity), not the collision speed with Earth. (I was addressing John's apparent concern with the highest speed meteors in the diagrams.)
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
JohnD
Tea Time, Guv! Cheerio!
Posts: 1042
Joined: Wed Feb 16, 2005 2:11 pm
Location: Lancaster, England

Re: Extra-solar fireballs??

Post by JohnD » Thu Jun 14, 2018 3:17 pm

Chris Peterson wrote:
Thu Jun 14, 2018 1:48 pm
JohnD wrote:
Thu Jun 14, 2018 7:38 am
Thanks, Chris. So their apparent extrasolar origins due to inadequate data.
No, there is a rich, accurate dataset. What is it that makes you think there are apparent extrasolar origins? The color coded speed range extends from the slowest possible meteors (Earth's escape velocity, 11 km/s), to the fastest possible meteors from solar-bound objects (72 km/s). None of the meteors are observed moving faster than 72 km/s, which means they are all in solar orbit.
Can't repost the graphic here, but you may be able to find it in SpaceWeather. The slow objects are shown to have solar orbits, but the fast ones are shown as if coming straight in, from our of the planetary plane, and in straight lines. That's what made me ask, extrasolar??

User avatar
Chris Peterson
Abominable Snowman
Posts: 13805
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: Extra-solar fireballs??

Post by Chris Peterson » Thu Jun 14, 2018 4:11 pm

JohnD wrote:
Thu Jun 14, 2018 3:17 pm
Chris Peterson wrote:
Thu Jun 14, 2018 1:48 pm
JohnD wrote:
Thu Jun 14, 2018 7:38 am
Thanks, Chris. So their apparent extrasolar origins due to inadequate data.
No, there is a rich, accurate dataset. What is it that makes you think there are apparent extrasolar origins? The color coded speed range extends from the slowest possible meteors (Earth's escape velocity, 11 km/s), to the fastest possible meteors from solar-bound objects (72 km/s). None of the meteors are observed moving faster than 72 km/s, which means they are all in solar orbit.
Can't repost the graphic here, but you may be able to find it in SpaceWeather. The slow objects are shown to have solar orbits, but the fast ones are shown as if coming straight in, from our of the planetary plane, and in straight lines. That's what made me ask, extrasolar??
No, they are not shown coming straight in. The graphic only displays the Solar System out to between Jupiter and Saturn. You can see the asteroidal meteors because the entire orbit is visible, with aphelions between Mars and Jupiter. But material from cometary origins often has very high eccentricities, and therefore high speeds when passing through the inner system. These fast meteors may look like they're traveling in nearly straight lines simply because we're zoomed in too close to see the full orbits, which may have an aphelions beyond Pluto- many meters off the center of your computer monitor.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
JohnD
Tea Time, Guv! Cheerio!
Posts: 1042
Joined: Wed Feb 16, 2005 2:11 pm
Location: Lancaster, England

Re: Extra-solar fireballs??

Post by JohnD » Fri Jun 15, 2018 7:34 am

Appreciating the size of astronomical matters often leads one astray.
Thank you, Chris!

John