[et_pb_section fb_built=”1″ admin_label=”Section” _builder_version=”4.16″ _module_preset=”default” background_image=”https:\/\/www.ieec.cat\/wp-content\/uploads\/2022\/02\/slider-comunicacio.jpg” max_height=”130px” custom_padding=”0px||0px||false|false” da_disable_devices=”off|off|off” global_colors_info=”{}” da_is_popup=”off” da_exit_intent=”off” da_has_close=”on” da_alt_close=”off” da_dark_close=”off” da_not_modal=”on” da_is_singular=”off” da_with_loader=”off” da_has_shadow=”on”][\/et_pb_section][et_pb_section fb_built=”1″ admin_label=”Section” _builder_version=”4.16″ _module_preset=”default” custom_padding=”24px||11px|||” da_disable_devices=”off|off|off” global_colors_info=”{}” da_is_popup=”off” da_exit_intent=”off” da_has_close=”on” da_alt_close=”off” da_dark_close=”off” da_not_modal=”on” da_is_singular=”off” da_with_loader=”off” da_has_shadow=”on”][et_pb_row _builder_version=”4.16″ _module_preset=”default” custom_padding=”||||false|false” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_text admin_label=”Unitats de recerca” module_class=”ieec-orgs” _builder_version=”4.27.4″ _dynamic_attributes=”content” _module_preset=”default” text_font=”|700||on|||||” text_font_size=”16px” header_font=”|700|||||||” custom_margin=”||10px||false|false” header_font_size_tablet=”28px” header_font_size_phone=”26px” header_font_size_last_edited=”on|phone” global_colors_info=”{}”]@ET-DC@eyJkeW5hbWljIjp0cnVlLCJjb250ZW50IjoiY3VzdG9tX21ldGFfb3JnYW5pemFjaW9uZXMiLCJzZXR0aW5ncyI6eyJiZWZvcmUiOiIiLCJhZnRlciI6IiIsImVuYWJsZV9odG1sIjoib2ZmIn19@[\/et_pb_text][et_pb_post_title author=”off” categories=”off” comments=”off” featured_image=”off” admin_label=”T\u00edtol i data” module_class=”ieec-title” _builder_version=”4.27.6″ _module_preset=”default” title_font=”Cairo|300|||||||” title_font_size=”40px” meta_font=”||on||||||” meta_font_size=”16px” title_font_size_tablet=”35px” title_font_size_phone=”30px” title_font_size_last_edited=”on|desktop” global_colors_info=”{}”][\/et_pb_post_title][et_pb_text admin_label=”Subt\u00edtols” module_class=”ieec-summary” _builder_version=”4.27.6″ _module_preset=”default” text_font=”Source Sans Pro||on||||||” text_font_size=”24px” text_line_height=”1.1em” hover_enabled=”0″ text_font_size_tablet=”22px” text_font_size_phone=”20px” text_font_size_last_edited=”on|phone” global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n
[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row column_structure=”1_2,1_2″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_column type=”1_2″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_post_title title=”off” meta=”off” module_class=”ieec-img-container” _builder_version=”4.27.2″ _module_preset=”default” custom_margin=”||0px||false|false” border_width_top=”10px” border_color_top=”#406fda” global_colors_info=”{}”][\/et_pb_post_title][et_pb_text module_class=”ieec-img-footer” _builder_version=”4.27.6″ _module_preset=”default” text_font=”||||||||” text_font_size=”15px” text_line_height=”1.1em” background_color=”rgba(64,111,218,0.15)” custom_margin=”0px||||false|false” custom_padding=”30px|20px|30px|20px|true|true” hover_enabled=”0″ global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n
A frame from the Auriga simulations, which study galaxies similar to the Milky Way. Matthew Orkney and Chervin Laporte<\/strong><\/p>\n [\/et_pb_text][\/et_pb_column][et_pb_column type=”1_2″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_text _builder_version=”4.27.6″ _module_preset=”default” link_font=”|700|||on||||” hover_enabled=”0″ global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n Ancient galactic collisions have a profound impact on the structural integrity of stellar discs in galaxies like our own. A recent study reveals how <\/span>these violent cosmic encounters can either partially or fully destroy the discs of stars<\/b> that define spiral galaxies. By combining advanced simulations of these collisions with observational data from star clusters, researchers have improved our ability to predict when the Milky Way experienced its last major galactic collision.<\/span><\/p>\n This breakthrough was led by researchers from the <\/span>Institute of Space Studies of Catalonia<\/span><\/a> (IEEC \u2014 Institut d\u2019Estudis Espacials de Catalunya) at the <\/span>Institute of Cosmos Sciences of the University of Barcelona<\/span><\/a> (ICCUB). The full findings are published in the Monthly Notices of the Royal Astronomical Society.<\/span><\/p>\n \u201cThis research highlights the important relationship between galactic structure and ancient collisions, which must be understood in unison in order to understand the history of our Galaxy,\u201d explains lead author Matthew D. A. Orkney, IEEC researcher at the ICCUB.<\/span><\/p>\n [\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_text module_class=”section-title” _builder_version=”4.27.6″ _module_preset=”default” header_2_font=”|700|||||||” header_2_font_size=”25px” hover_enabled=”0″ header_2_font_size_tablet=”23px” header_2_font_size_phone=”23px” header_2_font_size_last_edited=”on|phone” global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n [\/et_pb_text][et_pb_text _builder_version=”4.27.6″ _module_preset=”default” link_font=”|700|||on||||” hover_enabled=”0″ locked=”off” global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n The Milky Way disc is a vast, rotating system of stars shaped like a pancake, with spiral arms winding out from its centre. This disc contains most of the Galaxy\u2019s stars, including the Sun, and rotates at a speed of over 220 kilometers per second.<\/span><\/p>\n Astronomers have long tried to determine when this rotating disc first formed. One key clue comes from the motions and ages of stars: at some point in the Galaxy\u2019s early history, stars began to move in a coherent, rotating pattern, marking what scientists call the Galaxy\u2019s \u201cspin-up time.\u201d<\/span><\/p>\n However, the Milky Way did not form in isolation. For decades, scientists suspected that <\/span>a violent collision with a smaller galaxy played a major role in shaping the Milky Way we see today<\/b>. This suspicion was confirmed in 2018, when data from the <\/span>Gaia<\/span><\/a> mission revealed a large population of stars whose unusual motions could only be explained by a massive merger around 10 billion years ago. This event is now known as the Gaia-Sausage-Enceladus (GSE) merger.<\/span><\/p>\n In this new study, simulations of Milky Way-like galaxies (the Auriga simulations) are used to investigate how rotating discs form under a variety of different scenarios. These show how galaxies like our Milky Way react to ancient collisions.<\/span><\/p>\n [\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row column_structure=”1_2,1_2″ _builder_version=”4.27.6″ _module_preset=”default” global_colors_info=”{}”][et_pb_column type=”1_2″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_text module_class=”section-title” _builder_version=”4.27.6″ _module_preset=”default” header_2_font=”|700|||||||” header_2_font_size=”25px” hover_enabled=”0″ header_2_font_size_tablet=”23px” header_2_font_size_phone=”23px” header_2_font_size_last_edited=”on|phone” global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n [\/et_pb_text][et_pb_text _builder_version=”4.27.6″ _module_preset=”default” link_font=”|700|||on||||” hover_enabled=”0″ locked=”off” global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n The study shows that <\/span>rotating stellar discs often form much earlier than previously assumed<\/b>, but can be partially or completely destroyed by major galactic collisions. As a result, the moment when the Milky Way\u2019s disc appears to \u201cspin up\u201d may not mark the first time a disc formed, but rather the time when the Galaxy recovered from a destructive merger.<\/span><\/p>\n Using insights from these simulations, the authors infer that <\/span>the Gaia-Sausage-Enceladus merger likely occurred around 11 billion years ago<\/b>, earlier than many previous estimates. Crucially, this timing coincides with a sharp increase in the birth of star clusters in the Milky Way. Such bursts of star formation are a natural consequence of galactic collisions, which compress gas and trigger intense star formation.<\/span><\/p>\n [\/et_pb_text][\/et_pb_column][et_pb_column type=”1_2″ _builder_version=”4.27.6″ _module_preset=”default” global_colors_info=”{}”][et_pb_divider color=”#406fda” _builder_version=”4.16″ _module_preset=”default” custom_margin=”||10px||false|false” global_colors_info=”{}”][\/et_pb_divider][et_pb_text _builder_version=”4.27.6″ _module_preset=”default” text_font=”Cairo|700|||||||” text_text_color=”#406fda” text_font_size=”20px” custom_margin=”||10px||false|false” hover_enabled=”0″ global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n The evolution of a galaxy<\/p>\n [\/et_pb_text][et_pb_video src=”https:\/\/www.youtube.com\/watch?v=GbKLOUsBFYo” _builder_version=”4.27.6″ _module_preset=”default” custom_margin=”||4px|||” global_colors_info=”{}”][\/et_pb_video][et_pb_text module_class=”ieec-img-footer” _builder_version=”4.27.6″ _module_preset=”default” text_font=”||||||||” text_font_size=”15px” text_line_height=”1.1em” background_color=”rgba(64,111,218,0.15)” custom_margin=”0px||||false|false” custom_padding=”30px|20px|30px|20px|true|true” hover_enabled=”0″ locked=”off” global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n The Auriga simulations allow us to study the evolution of Milky Way-like galaxies. Matthew Orkney and Chervin Laporte<\/strong><\/p>\n [\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_text _builder_version=”4.27.6″ _module_preset=”default” link_font=”|700|||on||||” hover_enabled=”0″ locked=”off” global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n \u201cModels of the Gaia-Sausage-Enceladus merger predict that a Galactic firework should have followed from the impact, raising star formation and fostering the formation of globular clusters. This is the first time this link has been made.\u201d says collaborating author Chervin F. P. Laporte, researcher at CNRS.<\/span><\/p>\n Whilst scientists can never travel back in time to observe the Milky Way in its youth, they can observe the formation of similar galaxies in the distant Universe with new data from the James Webb Space Telescope (JWST) and the Atacama Large Millimeter\/submillimeter Array (ALMA), a powerful radio telescope.<\/span><\/p>\n [\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row _builder_version=”4.16″ _module_preset=”default” custom_margin=”30px||||false|false” locked=”off” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_divider color=”#406fda” _builder_version=”4.16″ _module_preset=”default” custom_margin=”||10px||false|false” global_colors_info=”{}”][\/et_pb_divider][et_pb_text admin_label=”M\u00e9s informaci\u00f3” module_class=”ieec-sub-title” _builder_version=”4.27.6″ _module_preset=”default” text_font=”Cairo|700|||||||” text_text_color=”#406fda” text_font_size=”20px” custom_margin=”||10px||false|false” hover_enabled=”0″ global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n More information<\/p>\n [\/et_pb_text][et_pb_text module_class=”ieec-sub-text” _builder_version=”4.27.6″ _module_preset=”default” text_font_size=”16px” text_line_height=”1.1em” link_font=”|700|||on||||” custom_margin=”20px||||false|false” hover_enabled=”0″ global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n This research is presented in a paper entitled \u201c<\/span>Build-up and survival of the disc: From numerical models of galaxy formation to the Milky Way<\/span><\/a>\u201d, by <\/span>Orkney, Matthew, and Laporte, Chervin<\/span>, to appear in the journal Monthly Notices of the Royal Astronomical Society in May 2026.<\/span><\/p>\n [\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row _builder_version=”4.16″ _module_preset=”default” custom_margin=”||||false|false” locked=”off” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_divider color=”#406fda” _builder_version=”4.16″ _module_preset=”default” custom_margin=”||10px||false|false” global_colors_info=”{}”][\/et_pb_divider][et_pb_text admin_label=”Enlla\u00e7os” module_class=”ieec-sub-title” _builder_version=”4.27.6″ _module_preset=”default” text_font=”Cairo|700|||||||” text_text_color=”#406fda” text_font_size=”20px” custom_margin=”||10px||false|false” hover_enabled=”0″ global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n Links<\/p>\n [\/et_pb_text][et_pb_text module_class=”ieec-sub-text” _builder_version=”4.27.6″ _module_preset=”default” text_font_size=”16px” text_line_height=”1.1em” link_font=”|700|||on|||#1a1140|” link_text_color=”#1a1140″ link_line_height=”1.4em” custom_margin=”20px||||false|false” global_colors_info=”{}”]<\/p>\n [\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row _builder_version=”4.16″ _module_preset=”default” custom_margin=”||||false|false” locked=”off” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_divider color=”#406fda” _builder_version=”4.16″ _module_preset=”default” custom_margin=”||10px||false|false” global_colors_info=”{}”][\/et_pb_divider][et_pb_text admin_label=”Contactes” module_class=”ieec-sub-title” _builder_version=”4.27.6″ _module_preset=”default” text_font=”Cairo|700|||||||” text_text_color=”#406fda” text_font_size=”20px” custom_margin=”||10px||false|false” hover_enabled=”0″ global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n Contacts<\/p>\n [\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row column_structure=”2_5,3_5″ admin_label=”Row” _builder_version=”4.16″ _module_preset=”default” custom_margin=”0px||||false|false” custom_padding=”0px||||false|false” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_column type=”2_5″ _builder_version=”4.16″ _module_preset=”default” custom_padding=”|||20px|false|false” border_width_left=”1px” border_color_left=”#406fda” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_text _builder_version=”4.16″ _module_preset=”default” text_font_size=”16px” text_line_height=”1.1em” link_font=”|700|||on|||#1a1140|” link_text_color=”#1a1140″ link_line_height=”1.4em” header_4_font=”|700|||||||” header_4_text_color=”#1a1140″ custom_margin=”||||false|false” locked=”off” global_colors_info=”{}” theme_builder_area=”post_content”]<\/p>\n Castelldefels, Barcelona [\/et_pb_text][\/et_pb_column][et_pb_column type=”3_5″ _builder_version=”4.16″ _module_preset=”default” custom_padding=”|||20px|false|false” border_width_left=”1px” border_color_left=”#406fda” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_text _builder_version=”4.27.6″ _module_preset=”default” text_font_size=”16px” text_line_height=”1em” link_font=”|700|||on||||” link_text_color=”#1a1140″ header_4_font=”|700|||||||” header_4_text_color=”#1a1140″ hover_enabled=”0″ global_colors_info=”{}” theme_builder_area=”post_content” sticky_enabled=”0″]<\/p>\n Institute of Space Studies of Catalonia (IEEC) [\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row module_id=”ieec-about” module_class=”about-ieec” _builder_version=”4.27.4″ _module_preset=”default” background_color=”rgba(64,111,218,0.15)” global_module=”17324″ global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.16″ _module_preset=”default” custom_padding=”20px|50px|20px|50px|true|true” global_colors_info=”{}”][et_pb_text admin_label=”Sobre l’IEEC” _builder_version=”4.16″ _module_preset=”default” header_2_font=”|700|||||||” header_2_font_size=”25px” custom_margin=”||10px||false|false” header_2_font_size_tablet=”23px” header_2_font_size_phone=”23px” header_2_font_size_last_edited=”on|phone” locked=”off” global_colors_info=”{}”]<\/p>\n [\/et_pb_text][et_pb_text admin_label=”Text” _builder_version=”4.16″ _module_preset=”default” text_font=”||on||||||” link_font=”|700|||on||||” locked=”off” global_colors_info=”{}”]<\/p>\n The Institute of Space Studies of Catalonia (IEEC \u2014 Institut d\u2019Estudis Espacials de Catalunya) promotes and coordinates space research and technology development in Catalonia for the benefit of society. IEEC fosters collaborations both locally and worldwide and is an efficient agent of knowledge, innovation and technology transfer. As a result of more than 25 years of high-quality research, done in collaboration with major international organisations, IEEC ranks among the best international research centres, focusing on areas such as: astrophysics, cosmology, planetary science, and Earth Observation. IEEC\u2019s engineering division develops instrumentation for ground- and space-based projects, and has extensive experience in working with private or public organisations from the aerospace and other innovation sectors.<\/p>\n The IEEC is a non-profit public sector foundation that was established in February 1996. It has a Board of Trustees composed of the Generalitat de Catalunya, Universitat de Barcelona (UB), Universitat Aut\u00f2noma de Barcelona (UAB), Universitat Polit\u00e8cnica de Catalunya \u00b7 BarcelonaTech (UPC), and the Spanish Research Council (CSIC). The IEEC is also a CERCA centre.<\/p>\n [\/et_pb_text][\/et_pb_column][\/et_pb_row][\/et_pb_section]<\/p>\n","protected":false},"excerpt":{"rendered":" Combining simulations with observational data, researchers infer that the last major collision of our galaxy likely occurred around 11 billion years ago.<\/p>\n","protected":false},"author":5,"featured_media":45006,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"on","_et_pb_old_content":"","_et_gb_content_width":"2880","footnotes":""},"categories":[111,74,98],"tags":[],"class_list":["post-45005","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-highlighted-news-small","category-news","category-science"],"yoast_head":"\nWhen did the Milky Way disc spin up?<\/h2>\n
Key findings<\/h2>\n
\n
IEEC Communication Office<\/h4>\n
E-mail: comunicacio@ieec.cat<\/a><\/p>\nLead Researcher at the IEEC<\/h4>\n
Matthew Orkney<\/h4>\n
Institute of Cosmos Sciences (ICCUB)
E-mail: morkney@ieec.cat,<\/a> morkney@icc.ub.edu<\/a><\/p>\nAbout the IEEC<\/h2>\n