APOD: Asteroids in the Distance (2021 Jan 31)

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 4840
Joined: Fri Dec 04, 2009 3:27 am

APOD: Asteroids in the Distance (2021 Jan 31)

Post by APOD Robot » Sun Jan 31, 2021 5:07 am

Image Asteroids in the Distance

Explanation: Rocks from space hit Earth every day. The larger the rock, though, the less often Earth is struck. Many kilograms of space dust pitter to Earth daily. Larger bits appear initially as a bright meteor. Baseball-sized rocks and ice-balls streak through our atmosphere daily, most evaporating quickly to nothing. Significant threats do exist for rocks near 100 meters in diameter, which strike the Earth roughly every 1000 years. An object this size could cause significant tsunamis were it to strike an ocean, potentially devastating even distant shores. A collision with a massive asteroid, over 1 km across, is more rare, occurring typically millions of years apart, but could have truly global consequences. Many asteroids remain undiscovered. In the featured image, one such asteroid -- shown by the long blue streak -- was found by chance in 1998 by the Hubble Space Telescope. A collision with a large asteroid would not affect Earth's orbit so much as raise dust that would affect Earth's climate. One likely result is a global extinction of many species of life, possibly dwarfing the ongoing extinction occurring now.

<< Previous APOD This Day in APOD Next APOD >>

RocketRon

Re: APOD: Asteroids in the Distance (2021 Jan 31)

Post by RocketRon » Sun Jan 31, 2021 5:13 am

If it doesn't happen soon-ish, the current extinction rates over the longer term may not leave much anyway ?

Back to basics first maybe though.
What are all the blues and yellows in this image ?

User avatar
Holger Nielsen
Ensign
Posts: 43
Joined: Fri Oct 14, 2016 7:45 am

Re: APOD: Asteroids in the Distance (2021 Jan 31)

Post by Holger Nielsen » Sun Jan 31, 2021 8:41 am

According to the link given (https://hubblesite.org/image/616/category/39-asteroids) they "were created by cosmic rays, energetic subatomic particles that struck the camera's detector". But I don't understand why some are colored yellow and others blue.

User avatar
Ann
4725 Å
Posts: 12351
Joined: Sat May 29, 2010 5:33 am

Re: APOD: Asteroids in the Distance (2021 Jan 31)

Post by Ann » Sun Jan 31, 2021 10:18 am

Holger Nielsen wrote: Sun Jan 31, 2021 8:41 am According to the link given (https://hubblesite.org/image/616/category/39-asteroids) they "were created by cosmic rays, energetic subatomic particles that struck the camera's detector". But I don't understand why some are colored yellow and others blue.
I think - mind you, I think - that the asteroid was caught by the cyan filter of Hubble. The short yellow streaks might just be asteroids caught by the orange filter of Hubble.

As for the blue and yellow "very short streaks" that are seen all over the image, I think many of them may be cosmic rays, caught by either the cyan or the orange filter.

It seems obvious that Hubble was busy taking a two-filter color image, using a cyan and an orange filter for the image. To see what such a two-filter Hubble color image might look like, I recommend the picture of galaxy NGC 2683.

Ann
Color Commentator

User avatar
Holger Nielsen
Ensign
Posts: 43
Joined: Fri Oct 14, 2016 7:45 am

Re: APOD: Asteroids in the Distance (2021 Jan 31)

Post by Holger Nielsen » Sun Jan 31, 2021 1:04 pm

Yes, of course, Ann, you must be right, its a filter effect! Thank you, Color Commentator. As to the short yellow streaks, I think they are due to cosmic rays just as the very short streaks, perhaps coming in at a low angle. Asteroids at the same distance would create streaks of about the same length. But on the other hand the long blue streak could originate from a *very* close asteroid. To distinguish one would have to know the exposure time and the image scale.

User avatar
orin stepanek
Plutopian
Posts: 7806
Joined: Wed Jul 27, 2005 3:41 pm
Location: Nebraska

Re: APOD: Asteroids in the Distance (2021 Jan 31)

Post by orin stepanek » Sun Jan 31, 2021 1:21 pm

AsteroidStreak_hst_960.jpg

Rocks in Space; Earth must be getting bigger from all the impacts! :mrgreen:
You do not have the required permissions to view the files attached to this post.
Orin

Smile today; tomorrow's another day!

Sa Ji Tario

Re: APOD: Asteroids in the Distance (2021 Jan 31)

Post by Sa Ji Tario » Sun Jan 31, 2021 1:57 pm

I understand that the Earth grows about 4,000 tons of dust per year that we receive by the Pointing-Robertson effect

User avatar
Chris Peterson
Abominable Snowman
Posts: 17009
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: Asteroids in the Distance (2021 Jan 31)

Post by Chris Peterson » Sun Jan 31, 2021 2:22 pm

Holger Nielsen wrote: Sun Jan 31, 2021 1:04 pm Yes, of course, Ann, you must be right, its a filter effect! Thank you, Color Commentator. As to the short yellow streaks, I think they are due to cosmic rays just as the very short streaks, perhaps coming in at a low angle. Asteroids at the same distance would create streaks of about the same length. But on the other hand the long blue streak could originate from a *very* close asteroid. To distinguish one would have to know the exposure time and the image scale.
Also, keep in mind that cosmic rays often hit structure around the camera and create a particle cascade. We call all those artifacts in the image "cosmic ray hits", but many are the result of secondary hits. So there is a wide range of both energies and impact angles.

These are normally removed by stacking together multiple images using some kind of median processing. But when you're looking at a moving object like an asteroid, you can't do that.
Chris

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

User avatar
Chris Peterson
Abominable Snowman
Posts: 17009
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: Asteroids in the Distance (2021 Jan 31)

Post by Chris Peterson » Sun Jan 31, 2021 2:57 pm

Sa Ji Tario wrote: Sun Jan 31, 2021 1:57 pm I understand that the Earth grows about 4,000 tons of dust per year that we receive by the Pointing-Robertson effect
Probably more in the range of 100,000 to 1,000,000 tons. And only some is delivered from outside our orbit by the Poynting-Roberson effect. We encounter material from inside our orbit being pushed outward by solar wind and radiation pressure, we encounter cometary debris in orbits that intersect our own, we encounter material larger than dust that is perturbed into orbits that cross ours.
Chris

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

Sa Ji Tario

Re: APOD: Asteroids in the Distance (2021 Jan 31)

Post by Sa Ji Tario » Sun Jan 31, 2021 3:07 pm

Thank you Chris

Wadsworth
Science Officer
Posts: 131
Joined: Tue Jun 20, 2006 3:12 pm
Location: TX

Re: APOD: Asteroids in the Distance (2021 Jan 31)

Post by Wadsworth » Sun Jan 31, 2021 4:24 pm

It's a little confusing for me to understand how Hubble caught a picture of an asteroid burning up in our atmosphere.
Is there still enough atmosphere where Hubble is in orbit that it can catch an asteroid burning up while pointed away from the Earth?
Or was this image captured when Hubble was pointed more towards Earth, catching the asteroid from a 'side' angle?

User avatar
Chris Peterson
Abominable Snowman
Posts: 17009
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: Asteroids in the Distance (2021 Jan 31)

Post by Chris Peterson » Sun Jan 31, 2021 4:32 pm

Wadsworth wrote: Sun Jan 31, 2021 4:24 pm It's a little confusing for me to understand how Hubble caught a picture of an asteroid burning up in our atmosphere.
Is there still enough atmosphere where Hubble is in orbit that it can catch an asteroid burning up while pointed away from the Earth?
Or was this image captured when Hubble was pointed more towards Earth, catching the asteroid from a 'side' angle?
These asteroids are not in our atmosphere. They are in orbit around the Sun, in space.
Chris

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

User avatar
neufer
Vacationer at Tralfamadore
Posts: 18805
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Dust Miteorites

Post by neufer » Sun Jan 31, 2021 7:28 pm

APOD Robot wrote: Sun Jan 31, 2021 5:07 am
Explanation: Many kilograms of space dust pitter to Earth daily.
Henry Wadsworth Longfellow, "The Children's Hour" wrote:
  • : Between the dark and the daylight,
    : When the night is beginning to lower,
    : Comes a pause in the day's occupations,
    : That is known as the Children's Hour.

    : I hear in the chamber above me
    : The patter of little feet,
    : The sound of a door that is opened,
    : And voices soft and sweet.
................................................................
pitter-patter : a series of quick, light knocking sounds:

"I heard the pitter-patter of tiny feet." (dust mite radius ~ 1.5 x 10-4 m)
Chris Peterson wrote: Sun Jan 31, 2021 2:57 pm
Sa Ji Tario wrote: Sun Jan 31, 2021 1:57 pm
I understand that the Earth grows about 4,000 tons of dust per year that we receive by the Pointing-Robertson effect
Probably more in the range of 100,000 to 1,000,000 tons. And only some is delivered from outside our orbit by the Poynting-Roberson effect. We encounter material from inside our orbit being pushed outward by solar wind and radiation pressure, we encounter cometary debris in orbits that intersect our own, we encounter material larger than dust that is perturbed into orbits that cross ours.
https://link.springer.com/article/10.1007/s11214-017-0458-1 wrote:
Impacts of Cosmic Dust on Planetary Atmospheres and Surfaces
by John M. C. Plane, George J. Flynn, Anni Määttänen, John E. Moores, Andrew R. Poppe, Juan Diego Carrillo-Sanchez & Constantino Listowski

Space Science Reviews volume 214, Article number: 23 (2018)
Published: 21 December 2017

Surface Accretion of Dust and Meteorites

<<The contribution by dust and meteorites to planetary surfaces was demonstrated by the Apollo samples. Elemental analyses showed that the Lunar regolith and regolith breccias had elevated levels of Ir, Au, Zn, Cd, Ag, Br, Bi, and Tl compared to the ordinary Lunar rocks in a pattern that indicated the addition of 1.5% to 2.0% carbonaceous chondrite-like material to the regolith (Keays et al. 1970; Anders et al. 1973). In the case of the Earth, the mass flux at the top of the atmosphere has been estimated by combining results from satellite impact measurements for small particles, radar meteors for intermediate size objects, and the cratering record for large objects, as discussed by Peucker-Ehrenbrink et al. (2016). As shown in Fig. 7, the mass-frequency distribution is bimodal, with peaks corresponding to the continuous, planet-wide input of dust and the infrequent impact of large bodies, with a minimal contribution from objects in the intermediate size range. Measurements of impacts onto the Long Duration Exposure Facility, which was in low-Earth orbit for about 69 months, indicate that the accretion rate of cosmic dust into the Earth’s atmosphere is 110±55 t/d [= 20,000 to 60,000 tonnes/year] in the current era (Love and Brownlee 1993). This is at least 100 times larger than the annual influx of meteorites (Bland et al. 1996), with particles in the narrow mass range from 10−8 to 10−3 g contributing more than 80% of the total mass flux of meteoritic material in the 10−13 to 106 g mass range incident on the Earth (Hughes 1978; Carrillo-Sánchez et al. 2016). Modeling by Carrillo-Sánchez et al. (2016) of the dust up to 500 μm in diameter indicates that the total mass input is 43±14 t/d, with 35.4 t/d surviving as either unmelted particles or melted spherules, and the remaining 7.9 t/d being deposited in the upper atmosphere as ablated atoms. The dust accretion rate was likely much greater during the first 0.6 billion years of Solar System history, when asteroids and comets were more abundant in the inner Solar System as evidenced by the higher impact rate of large objects on the Moon during the Late Heavy Bombardment (Hartmann et al. 2000).>>
https://en.wikipedia.org/wiki/Long_Duration_Exposure_Facility wrote:
<<NASA's Long Duration Exposure Facility, or LDEF (pronounced "eldef"), was a school bus-sized cylindrical facility designed to provide long-term experimental data on the outer space environment and its effects on space systems, materials, operations and selected spores' survival. It was placed in low Earth orbit by Space Shuttle Challenger in April 1984. LDEF successfully carried science and technology experiments for about 5.7 years that have revealed a broad and detailed collection of space environmental data. LDEF's 69 months in space provided scientific data on the long-term effects of space exposure on materials, components and systems that has benefited NASA spacecraft designers to this day.

The LDEF structure shape was a 12 sided prism (to fit the shuttle orbiter payload bay), and made entirely from stainless steel. There were 5 or 6 experiments on each of the 12 long sides and a few more on the ends. It was designed to fly with one end facing earth and the other away from earth. Attitude control of LDEF was achieved with gravity-gradient stabilization and inertial distribution to maintain three-axis stability in orbit. Therefore, propulsion or other attitude control systems were not required, making LDEF free of acceleration forces and contaminants from jet firings. There was also a magnetic/viscous damper to stop any initial oscillation after deployment.

At LDEF's launch, retrieval was scheduled for March 19, 1985, eleven months after deployment. Schedules slipped, postponing the retrieval mission first to 1986, then indefinitely due to the Challenger disaster. After 5.7 years its orbit had decayed to about 175 nautical miles and it was likely to burn up on reentry in a little over a month. It was finally recovered by Columbia on mission STS-32 on January 12, 1990. Columbia approached LDEF in such a way as to minimize possible contamination to LDEF from thruster exhaust. While LDEF was still attached to the RMS arm, an extensive 4.5 hour survey photographed each individual experiment tray, as well as larger areas. Nevertheless, shuttle operations did contaminate experiments when concerns for human comfort out-weighed important LDEF mission goals.>>
Last edited by neufer on Mon Feb 01, 2021 7:02 pm, edited 1 time in total.
Art Neuendorffer

FLPhotoCatcher
Science Officer
Posts: 225
Joined: Wed Jul 18, 2012 6:51 am

Re: APOD: Asteroids in the Distance (2021 Jan 31)

Post by FLPhotoCatcher » Mon Feb 01, 2021 4:21 pm

What is the name of the asteroid? I imagine it refers to the Hubble telescope?

FLPhotoCatcher
Science Officer
Posts: 225
Joined: Wed Jul 18, 2012 6:51 am

Re: APOD: Asteroids in the Distance (2021 Jan 31)

Post by FLPhotoCatcher » Mon Feb 01, 2021 4:26 pm

Are the fuzzy black blobs gas clouds, or dead pixel patches?

TheZuke!
Science Officer
Posts: 198
Joined: Fri Mar 22, 2019 2:19 pm

Re: APOD: Asteroids in the Distance (2021 Jan 31)

Post by TheZuke! » Tue Feb 02, 2021 2:25 pm

Ann wrote: Sun Jan 31, 2021 10:18 am
I think - mind you, I think
And therefore, you ARE!

:D

Michiel van der Wulp
Asternaut
Posts: 1
Joined: Thu Feb 04, 2021 8:39 am

Re: APOD: Asteroids in the Distance (2021 Jan 31)

Post by Michiel van der Wulp » Thu Feb 04, 2021 8:44 am

How come the blue line is not straight but curved?
Is the asteroid not flying in a straight line?

User avatar
Chris Peterson
Abominable Snowman
Posts: 17009
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: Asteroids in the Distance (2021 Jan 31)

Post by Chris Peterson » Thu Feb 04, 2021 1:37 pm

Michiel van der Wulp wrote: Thu Feb 04, 2021 8:44 am How come the blue line is not straight but curved?
Is the asteroid not flying in a straight line?
I think it's a parallax effect, a consequence of the fact that HST is imaging from low Earth orbit, tracking a sky that rotates every 95 minutes in a 28° inclination.
Chris

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