[{"command":"openDialog","selector":"#drupal-modal","settings":null,"data":"\u003Cdiv id=\u0022republish_modal_form\u0022\u003E\u003Cform class=\u0022modal-form-example-modal-form ecl-form\u0022 data-drupal-selector=\u0022modal-form-example-modal-form\u0022 action=\u0022\/da\/article\/modal\/7403\u0022 method=\u0022post\u0022 id=\u0022modal-form-example-modal-form\u0022 accept-charset=\u0022UTF-8\u0022\u003E\u003Cp\u003EHorizon articles can be republished for free under the Creative Commons Attribution 4.0 International (CC BY 4.0) licence.\u003C\/p\u003E\n      \u003Cp\u003EYou must give appropriate credit. We ask you to do this by:\u003Cbr \/\u003E\n      1) Using the original journalist\u0027s byline\u003Cbr \/\u003E\n      2) Linking back to our original story\u003Cbr \/\u003E\n      3) Using the following text in the footer: This article was originally published in \u003Ca href=\u0027#\u0027\u003EHorizon, the EU Research and Innovation magazine\u003C\/a\u003E\u003C\/p\u003E\n      \u003Cp\u003ESee our full republication guidelines \u003Ca href=\u0027\/horizon-magazine\/republish-our-stories\u0027\u003Ehere\u003C\/a\u003E\u003C\/p\u003E\n      \u003Cp\u003EHTML for this article, including the attribution and page view counter, is below:\u003C\/p\u003E\u003Cdiv class=\u0022js-form-item form-item js-form-type-textarea form-item-body-content js-form-item-body-content ecl-form-group ecl-form-group--text-area form-no-label ecl-u-mv-m\u0022\u003E\n        \n\u003Cdiv\u003E\n  \u003Ctextarea data-drupal-selector=\u0022edit-body-content\u0022 aria-describedby=\u0022edit-body-content--description\u0022 id=\u0022edit-body-content\u0022 name=\u0022body_content\u0022 rows=\u00225\u0022 cols=\u002260\u0022 class=\u0022form-textarea ecl-text-area\u0022\u003E\u003Ch2\u003EHow scientists are \u2018looking\u2019 inside asteroids\u003C\/h2\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EOnly \u003Ca href=\u0022https:\/\/www.theguardian.com\/science\/2020\/dec\/05\/hayabusa2-comes-home-remarkable-space-probe-could-open-another-window-into-how-life-originated\u0022 rel=\u0022noopener noreferrer\u0022 target=\u0022_blank\u0022\u003Efour spacecraft\u003C\/a\u003E have ever landed on an asteroid \u2013 most recently in \u003Ca href=\u0022https:\/\/www.theguardian.com\/science\/2020\/oct\/21\/nasa-osiris-rex-spacecraft-lands-on-asteroid-bennu-in-mission-to-collect-dust\u0022 rel=\u0022noopener noreferrer\u0022 target=\u0022_blank\u0022\u003EOctober 2020\u003C\/a\u003E \u2013 but none has peered inside one. Yet understanding the internal structures of these cosmic rocks is crucial for answering key questions about, for example, the origins of our own planet.\u003C\/p\u003E\u003Cp\u003E\u2018Asteroids are the only objects in our solar system that are more or less unchanged since the very beginning of the solar system\u2019s formation,\u2019 said Dr Fabio Ferrari, who studies asteroid dynamics at the University of Bern, Switzerland. \u2018If we know what\u2019s inside asteroids, we can understand a lot about how planets formed, how everything that we have in our solar system has formed and might evolve in the future.\u2019\u003C\/p\u003E\u003Cp\u003EThen are also more practical reasons for knowing what\u2019s inside an asteroid, such as mining for materials to facilitate human exploration of other celestial bodies, but also defending against an Earth-bound rock.\u003C\/p\u003E\u003Cp\u003ENASA\u2019s upcoming \u003Ca href=\u0022https:\/\/www.nasaspaceflight.com\/2021\/02\/dart-laucnh-delayed-to-november\/\u0022 rel=\u0022noopener noreferrer\u0022 target=\u0022_blank\u0022\u003EDouble Asteroid Redirection Test\u003C\/a\u003E (DART) mission, expected to launch later this year, will crash into the 160m in diameter asteroid moon Dimorphos in 2022, with the aim of changing its orbit. The experiment will demonstrate for the first time whether humans can deflect a potentially dangerous asteroid.\u003C\/p\u003E\u003Cp\u003EBut scientists have only rough ideas about how Dimorphos will respond to the impact as they know very little about both this asteroid moon, and its parent asteroid, Didymos.\u003C\/p\u003E\u003Cp\u003ETo better address such questions, scientists are investigating how to remotely tell what\u2019s inside an asteroid and discern its type.\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ETypes\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EThere are many types of asteroids. Some are solid blocks of rock, rugged and sturdy, others are conglomerates of pebbles, boulders and sand, products of many orbital collisions, held together only by the power of gravity. There are also rare metallic asteroids, heavy and dense.\u003C\/p\u003E\u003Cp\u003E\u2018To deflect the denser monolithic asteroids, you would need a bigger spacecraft, you would need to travel faster,\u2019 said Dr Hannah Susorney, a research fellow in planetary science at the University of Bristol, the UK. \u2018The asteroids that are just bags of material \u2013 we call them rubble piles \u2013 can, on the other hand, blow apart into thousands of pieces. Those pieces could by themselves become dangerous.\u2019\u003C\/p\u003E\u003Cp\u003EDr Susorney is exploring what surface features of an asteroid can reveal about the structure of its interior as part of a project called \u003Ca href=\u0022https:\/\/cordis.europa.eu\/project\/id\/837894\u0022 rel=\u0022noopener noreferrer\u0022 target=\u0022_blank\u0022\u003EEROS\u003C\/a\u003E. \u0026nbsp;\u003C\/p\u003E\u003Cp\u003EThis information could be useful for future \u003Ca href=\u0022https:\/\/www.businessinsider.com\/asteroid-mining-company-earth-startups-raw-materials-cobalt-gold-platinum-2021-3?r=US\u0026amp;IR=T\u0022 rel=\u0022noopener noreferrer\u0022 target=\u0022_blank\u0022\u003Espace mining companies\u003C\/a\u003E who would want to know as much as possible about a promising asteroid before investing into a costly prospecting mission as well as knowing more about potential threats.\u003C\/p\u003E\u003Cp\u003E\u2018There are thousands of near-Earth asteroids, those whose trajectories could one day intersect with that of the Earth,\u2019 she said. \u2018We have only visited a handful of them. We know close to nothing about the vast majority.\u2019\u003C\/p\u003E\u003Cp\u003E\u003Cfigure role=\u0022group\u0022 class=\u0022@alignleft@\u0022\u003E\n\u003Cimg alt=\u0022During the fourth ever landing on an asteroid, Bennu was mapped thanks to a mosaic of images collected by NASA\u2019s OSIRIS-REx spacecraft. Peering inside an asteroid is the next crucial step. Image credit - NASA\/Goddard\/University of Arizona\u0022 data-entity-type data-entity-uuid height=\u0022521\u0022 src=\u0022\/sites\/default\/files\/hm\/IMCEUpload\/bennu_global_mosaic_reduced_size.png\u0022 title=\u0022During the fourth ever landing on an asteroid, Bennu was mapped thanks to a mosaic of images collected by NASA\u2019s OSIRIS-REx spacecraft. Peering inside an asteroid is the next crucial step. Image credit - NASA\/Goddard\/University of Arizona\u0022 width=\u00221041\u0022\u003E\n\u003Cfigcaption class=\u0022italic mb-4\u0022\u003EDuring the fourth ever landing on an asteroid, Bennu was mapped thanks to a mosaic of images collected by NASA\u2019s OSIRIS-REx spacecraft. Peering inside an asteroid is the next crucial step. Image credit - NASA\/Goddard\/University of Arizona\u003C\/figcaption\u003E\n\u003C\/figure\u003E\n\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ETopography\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EDr Susorney is trying to create detailed topography models of two of the most well-studied asteroids \u2013 Itokawa (the target of the 2005 Japanese Hayabusa 1 mission) and Eros (mapped in detail by the NEAR Shoemaker space probe in the late 1990s).\u003C\/p\u003E\u003Cp\u003E\u2018The surface topography can actually tell us a lot,\u2019 Dr Susorney said. \u2018If you have a rubble pile asteroid, such as Itokawa, which is essentially just a bag of fluff, you cannot expect very steep slopes there. Sand cannot be held up into an infinite slope unless it\u2019s supported. A solid cliff can. The rocky monolithic asteroids, such as Eros, do tend to have much more pronounced topographical features, much deeper and steeper craters.\u2019\u003C\/p\u003E\u003Cp\u003ESusorney wants to take the high-resolution models derived from spacecraft data and find parameters in them that could then be used in the much lower resolution asteroid shape models created from ground-based radar observations.\u003C\/p\u003E\u003Cp\u003E\u2018The difference in the resolution is quite substantial,\u2019 she admits. \u2018Tens to hundreds of metres in the high-res spacecraft models and kilometres from ground-based radar measurements. But we have found that, for example, the slope distribution gives us a hint. How much of the asteroid is flat and how much is steep?\u2019\u003C\/p\u003E\u003Cp\u003E\u003Cfigure role=\u0022group\u0022 class=\u0022@alignleft@\u0022\u003E\n\u003Cimg alt=\u0022Coloured topographical maps from Dr Susorney show Eros (left), a rocky monolithic asteroid, as having steeper craters than Itokawa (right), a rubble pile asteroid. Image credit - Hannah Susorney\u0022 data-entity-type data-entity-uuid height=\u0022466\u0022 src=\u0022\/sites\/default\/files\/hm\/IMCEUpload\/erosz.jpg\u0022 title=\u0022Coloured topographical maps from Dr Susorney show Eros (left), a rocky monolithic asteroid, as having steeper craters than Itokawa (right), a rubble pile asteroid. Image credit - Hannah Susorney\u0022 width=\u0022973\u0022\u003E\n\u003Cfigcaption class=\u0022italic mb-4\u0022\u003EColoured topographical maps from Dr Susorney show Eros (left), a rocky monolithic asteroid, as having steeper craters than Itokawa (right), a rubble pile asteroid. Image credit - Hannah Susorney\u003C\/figcaption\u003E\n\u003C\/figure\u003E\n\u003C\/p\u003E\u003Cp\u003EDr Ferrari is working with the team preparing the DART mission. As part of a project called \u003Ca href=\u0022https:\/\/cordis.europa.eu\/project\/id\/800060\u0022 rel=\u0022noopener noreferrer\u0022 target=\u0022_blank\u0022\u003EGRAINS\u003C\/a\u003E, he developed a tool that enables modelling of the interior of Dimorphos, the impact target, as well as other rubble pile asteroids.\u003C\/p\u003E\u003Cp\u003E\u2018We expect that Dimorphos is a rubble pile because we think that it formed from matter ejected by the main asteroid, Didymos, when it was spinning very fast,\u2019 Dr Ferrari said. \u2018This ejected matter then re-accreted and formed the moon. But we have no observations of its interior.\u2019\u003C\/p\u003E\u003Cp\u003EAn aerospace engineer by education, Dr Ferrari borrowed a solution for the asteroid problem from the engineering world, from a discipline called granular dynamics.\u003C\/p\u003E\u003Cp\u003E\u2018On Earth, this technique can be used to study problems such as sand piling or various industrial processes involving small particles,\u2019 Dr Ferrari said. \u2018It\u2019s a numerical tool that allows us to model the interaction between the different particles (components) - in our case, the various boulders and pebbles inside the asteroid.\u2019\u003C\/p\u003E\u003Cp\u003E\u003Cblockquote class=\u0022text-center text-blue font-bold text-2xl w-full lg:w-1\/2 border-2 border-blue p-12 my-8 lg:m-12 lg:-ml-16 float-left\u0022\u003E\n  \u003Cspan class=\u0022text-5xl rotate-180\u0022\u003E\u201c\u003C\/span\u003E\n  \u003Cp class=\u0022font-serif italic\u0022\u003E\u2018Asteroids are the only objects in our solar system that are more or less unchanged since the very beginning of the solar system\u2019s formation.\u2019\u003C\/p\u003E\n  \u003Cfooter\u003E\n    \u003Ccite class=\u0022not-italic font-normal text-sm text-black\u0022\u003EDr Fabio Ferrari, University of Bern, Switzerland\u003C\/cite\u003E\n  \u003C\/footer\u003E\n\u003C\/blockquote\u003E\n\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ERubble pile\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EThe researchers are modelling various shapes and sizes, various compositions of the boulders and pebbles, the gravitational interactions and the friction between them. They can run thousands of such simulations and then compare them with surface data about known asteroids to understand rubble pile asteroids\u2019 behaviour and make-up.\u003C\/p\u003E\u003Cp\u003E\u2018We can look at the external shape, study various features on the surface, and compare that with our simulations,\u2019 Dr Ferrari said. \u2018For example, some asteroids have a prominent equatorial bulge,\u2019 he says, referring to the thickening around the equator that can appear as a result of the asteroid spinning.\u003C\/p\u003E\u003Cp\u003EIn the simulations, the bulge might appear more prominent for some internal structures than others.\u003C\/p\u003E\u003Cp\u003EFor the first time, Dr Ferrari added, the tool can work with non-spherical elements, which considerably improves accuracy.\u003C\/p\u003E\u003Cp\u003E\u2018Spheres behave very differently from angular objects,\u2019 he said.\u003C\/p\u003E\u003Cp\u003EThe model suggests that in the case of Dimorphos, the DART impact will create a crater and throw up a lot of material from the asteroid\u2019s surface. But there are still many questions, particularly the size of the crater, according to Dr Ferrari.\u003C\/p\u003E\u003Cp\u003E\u2018The crater might be as small as ten metres but also as wide as a hundred metres, taking up half the size of the asteroid. We don\u2019t really know,\u2019 said Dr Ferrari. \u2018Rubble piles are tricky. Because they are so loose, they might as well just absorb the impact.\u2019\u003C\/p\u003E\u003Cp\u003ENo matter what happens on Dimorphos, the experiment will provide a treasure trove of data for refining future simulations and models. We can see whether the asteroid behaves as we expected and learn how to make more accurate predictions for future missions that lives on Earth may very well depend on.\u003C\/p\u003E\u003Cp\u003E\u003Cfigure role=\u0022group\u0022 class=\u0022@aligneleft@\u0022\u003E\n\u003Cimg alt=\u0022The solar system\u2019s asteroid belt contains C-type asteroids, which likely consist of clay and silicate rocks, M-type, which are composed mainly of metallic iron, and S-type, which are formed of silicate materials and nickel-iron. Image credit - Horizon\u0022 data-entity-type data-entity-uuid height=\u00221435\u0022 src=\u0022\/sites\/default\/files\/hm\/IMCEUpload\/asteroids_-983_0.jpg\u0022 title=\u0022The solar system\u2019s asteroid belt contains C-type asteroids, which likely consist of clay and silicate rocks, M-type, which are composed mainly of metallic iron, and S-type, which are formed of silicate materials and nickel-iron. Image credit - Horizon\u0022 width=\u0022983\u0022\u003E\n\u003Cfigcaption class=\u0022italic mb-4\u0022\u003EThe solar system\u2019s asteroid belt contains C-type asteroids, which likely consist of clay and silicate rocks, M-type, which are composed mainly of metallic iron, and S-type, which are formed of silicate materials and nickel-iron. Image credit - Horizon\u003C\/figcaption\u003E\n\u003C\/figure\u003E\n\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EThe research in this article was funded by the EU. If you liked this article, please consider sharing it on social media.\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EThis article was originally published on 19 April 2021.\u003C\/em\u003E\u003C\/p\u003E\u003C\/textarea\u003E\n\u003C\/div\u003E\n\n            \u003Cdiv id=\u0022edit-body-content--description\u0022 class=\u0022ecl-help-block description\u0022\u003E\n      Please copy the above code and embed it onto your website to republish.\n    \u003C\/div\u003E\n  \u003C\/div\u003E\n\u003Cinput autocomplete=\u0022off\u0022 data-drupal-selector=\u0022form-8d3-z8am-c0pujygdosy6tj53smfuspihlxxfehg2e4\u0022 type=\u0022hidden\u0022 name=\u0022form_build_id\u0022 value=\u0022form-8D3-Z8AM_C0PUjYgdosy6tJ53SMfuspIHlxxFeHG2E4\u0022 \/\u003E\n\u003Cinput data-drupal-selector=\u0022edit-modal-form-example-modal-form\u0022 type=\u0022hidden\u0022 name=\u0022form_id\u0022 value=\u0022modal_form_example_modal_form\u0022 \/\u003E\n\u003C\/form\u003E\n\u003C\/div\u003E","dialogOptions":{"width":"800","modal":true,"title":"Republish this content"}}]