More results from DART impact of Dimorphos
Click for movie.
At a science conference this week scientists provided an update on the changes that occurred to the asteroid Dimorphos after it was impacted by the DART spacecraft in September, shortening its orbit around the larger asteroid Didymos by 33 minutes.
The image to the right is a screen capture from a short movie made from 30 images taken by the Magdalena Ridge Observatory in New Mexico, and part of a new image release of the asteroid pair.
It shows the motion of the Didymos system across the sky over the course of roughly 80 minutes, and features a long, linear tail stretching to the right from the asteroid system to the edge of the frame. The animation is roughly 32,000 kilometers across the field of view at the distance of Didymos.
According to the scientists, the impact displaced more than two million pounds of material from Dimorphos.
Observations before and after impact, reveal that Dimorphos and its larger parent asteroid, Didymos, have similar makeup and are composed of the same material – material that has been linked to ordinary chondrites, similar to the most common type of meteorite to impact the Earth. These measurements also took advantage of the ejecta from Dimorphos, which dominated the reflected light from the system in the days after impact. Even now, telescope images of the Didymos system show how solar radiation pressure has stretched the ejecta stream into a comet-like tail tens of thousands of miles in length.
Putting those pieces together, and assuming that Didymos and Dimorphos have the same densities, the team calculates that the momentum transferred when DART hit Dimorphos was roughly 3.6 times greater than if the asteroid had simply absorbed the spacecraft and produced no ejecta at all – indicating the ejecta contributed to moving the asteroid more than the spacecraft did.
This information is teaching us a great deal about these two particular asteroids, which could be used if for some reason their totally safe orbit got changed and they were going to impact Earth. However, NASA’s repeated effort to make believe this info would be useful for deflecting other asteroids is somewhat absurd. It is helpful, but each asteroid is unique. The data from DART is mostly helping astronomers get a better understanding of the geology of these specific asteroids, which will widen their understanding of asteroids in general. Planetary defense is really a very minor aspect of this work.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon. from any other book seller, or direct from my ebook publisher, ebookit.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Click for movie.
At a science conference this week scientists provided an update on the changes that occurred to the asteroid Dimorphos after it was impacted by the DART spacecraft in September, shortening its orbit around the larger asteroid Didymos by 33 minutes.
The image to the right is a screen capture from a short movie made from 30 images taken by the Magdalena Ridge Observatory in New Mexico, and part of a new image release of the asteroid pair.
It shows the motion of the Didymos system across the sky over the course of roughly 80 minutes, and features a long, linear tail stretching to the right from the asteroid system to the edge of the frame. The animation is roughly 32,000 kilometers across the field of view at the distance of Didymos.
According to the scientists, the impact displaced more than two million pounds of material from Dimorphos.
Observations before and after impact, reveal that Dimorphos and its larger parent asteroid, Didymos, have similar makeup and are composed of the same material – material that has been linked to ordinary chondrites, similar to the most common type of meteorite to impact the Earth. These measurements also took advantage of the ejecta from Dimorphos, which dominated the reflected light from the system in the days after impact. Even now, telescope images of the Didymos system show how solar radiation pressure has stretched the ejecta stream into a comet-like tail tens of thousands of miles in length.
Putting those pieces together, and assuming that Didymos and Dimorphos have the same densities, the team calculates that the momentum transferred when DART hit Dimorphos was roughly 3.6 times greater than if the asteroid had simply absorbed the spacecraft and produced no ejecta at all – indicating the ejecta contributed to moving the asteroid more than the spacecraft did.
This information is teaching us a great deal about these two particular asteroids, which could be used if for some reason their totally safe orbit got changed and they were going to impact Earth. However, NASA’s repeated effort to make believe this info would be useful for deflecting other asteroids is somewhat absurd. It is helpful, but each asteroid is unique. The data from DART is mostly helping astronomers get a better understanding of the geology of these specific asteroids, which will widen their understanding of asteroids in general. Planetary defense is really a very minor aspect of this work.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon. from any other book seller, or direct from my ebook publisher, ebookit. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
The information on this concept for changing asteroid orbits is quite useful. One of the possibilities for diverting a dangerous asteroid is to nudge another smaller asteroid into a collision course. The data from this mission suggests that impact may be more effective than previously thought. A kiloton impact at 10 km/sec could change the course of a gigaton monster by far more than previously thought. I called it Dinokiller eight ball in a blog post some years back. https://selenianboondocks.com/2013/03/dinokiller-eight-ball/
John hare wrote: “The data from this mission suggests that impact may be more effective than previously thought.”
Robert’s point is that “ each asteroid is unique.” If NASA had targeted the larger parent asteroid, Didymos, the results may have been different. If the larger astroid has less loose rock and other material, then the amplification factor most certainly would have been less. DART only gives us one data point, and its meaning needs much analysis to understand how this data point relates to any future data points that we may gather.
Essentially, this was low-hanging fruit. It was easy to reach, and being a double asteroid it is easy to manipulate and relatively quick to analyze the changes. Larger asteroids may not be as easy to collect this kind of data, and the data points gained from those experiments may take much longer to understand.
A possible followup mission could be to use a more massive probe on the same body, Dimorphos, to see how the differences in “bullets” affects the results. Starship comes to mind as a possible future bullet, being somewhere around 20 times more massive.
Fortunately, we do not know of any asteroids that are a real danger to us in the next few decades, so we have some time to gather more data before we are likely to have to use it in practice.
Edward: Though no impact mission is planned to this asteroid binary, a mission, Hera, to fly in formation with both to gather data on the consequences of the impact is scheduled for rendezvous with the asteroids in 2026. See: https://iopscience.iop.org/article/10.3847/PSJ/ac6f52
Robert,
From the abstract:
It looks like they will get some good geology from both asteroids.
Wouldn’t it be something if there were a second impactor experiment while Hera was still operational?
No wonder this sounds familiar. You mentioned the Hera mission a couple of months ago:
https://behindtheblack.com/behind-the-black/points-of-information/esa-delays-first-ariane-6-launch-to-late-in-2023/
https://behindtheblack.com/behind-the-black/points-of-information/darts-impact-shortened-dimorphuss-orbit-around-didymos-by-32-minutes/
I’m not sure a nickel-iron slug would have been affected much.