Christian Grefe
@cgrefe.bsky.social
Particle physicist at University of Bonn, working on the ATLAS experiment at CERN. https://orcid.org/0000-0001-7050-5301
Pinned
Christian Grefe
@cgrefe.bsky.social
· Nov 12
I guess it is time for a re- #introduction: I am a researcher at the University of Bonn and work on the @atlasexperiment.bsky.social at CERN. I post mostly about particle #physics, academia in Germany ( #IchBinHanna), and life in Geneva. 🧪⚛️
Happy new year! May 2026 be better than last year for all of you.
January 1, 2026 at 12:33 AM
Happy new year! May 2026 be better than last year for all of you.
Ausnahmsweise keine Berge die den Horizont versperren
December 26, 2025 at 5:11 PM
Ausnahmsweise keine Berge die den Horizont versperren
Heute gelernt: Wenn man bei der Deutschen Bahn mit Kleinkind bucht muss man nur die zusätzliche Sitzplatzreservierung bezahlen, ein extra Ticket gibt es nicht. Im Zug kann man dann aber nur die Anzahl der Tickets einchecken, nicht alle Sitzplätze. Selbst das Zugpersonal kann das nicht richtig machen
December 23, 2025 at 12:57 PM
Heute gelernt: Wenn man bei der Deutschen Bahn mit Kleinkind bucht muss man nur die zusätzliche Sitzplatzreservierung bezahlen, ein extra Ticket gibt es nicht. Im Zug kann man dann aber nur die Anzahl der Tickets einchecken, nicht alle Sitzplätze. Selbst das Zugpersonal kann das nicht richtig machen
For the first time private donors pledge significant funding for a major project at CERN: 860M CHF for the FCC (if approved).
home.cern/news/press-r...
home.cern/news/press-r...
Private donors pledge 860 million euros for CERN’s Future Circular Collider
For the first time in CERN’s history, private donors (individuals and philanthropic foundations) have agreed to support a CERN flagship research project. Recently, a group of friends of CERN, includin...
home.cern
December 18, 2025 at 4:35 PM
For the first time private donors pledge significant funding for a major project at CERN: 860M CHF for the FCC (if approved).
home.cern/news/press-r...
home.cern/news/press-r...
Some reflections on the recently published recommendations for the update of the European Strategy for particle #physics. newsline.linearcollider.org/2025/12/18/f... ⚛️🧪
First Reflections on the Recommendations of the European Strategy Group | ILC Newsline
The recently released recommendations of the European Strategy Group discuss Linear Colliders as technologically mature flagship projects which offer a competitive science program in Higgs and Top phy...
newsline.linearcollider.org
December 18, 2025 at 2:32 PM
Some reflections on the recently published recommendations for the update of the European Strategy for particle #physics. newsline.linearcollider.org/2025/12/18/f... ⚛️🧪
Reposted by Christian Grefe
📣 Pre-registration for Beamline for Schools (#BL4S) is open.
Beamline for Schools (#BL4S) is a #physics competition open to high-school students from all over the world.
Beamline for Schools (#BL4S) is a #physics competition open to high-school students from all over the world.
December 16, 2025 at 7:33 AM
📣 Pre-registration for Beamline for Schools (#BL4S) is open.
Beamline for Schools (#BL4S) is a #physics competition open to high-school students from all over the world.
Beamline for Schools (#BL4S) is a #physics competition open to high-school students from all over the world.
Reposted by Christian Grefe
The @iop.org has created a fun physics activity book with things for kids to do over the holiday break. 🎢 ⚛️ 🍎 🧪
www.iop.org/sites/defaul...
www.iop.org/sites/defaul...
www.iop.org
December 15, 2025 at 5:42 PM
The @iop.org has created a fun physics activity book with things for kids to do over the holiday break. 🎢 ⚛️ 🍎 🧪
www.iop.org/sites/defaul...
www.iop.org/sites/defaul...
Wer wissen will was passiert wenn #Lehrer sreiken dürfen kann das gerade in der Westschweiz beobachten. Über mehrer Wochen haben Lehrer und andere öffentliche Angestellte jeweils tageweise gestreikt. Grund: eine angekündigte Lohnkürzung um 0.7% ab Januar um zu sparen. www.srf.ch/news/schweiz...
Streik in der Waadt: Wenn die Schule plötzlich ausfällt
Mehr frei ist schön. Damit bleibt aber gerade an den Gymnasien weniger Zeit für die wichtigen Prüfungen vor Jahresende.
www.srf.ch
December 14, 2025 at 7:19 AM
Wer wissen will was passiert wenn #Lehrer sreiken dürfen kann das gerade in der Westschweiz beobachten. Über mehrer Wochen haben Lehrer und andere öffentliche Angestellte jeweils tageweise gestreikt. Grund: eine angekündigte Lohnkürzung um 0.7% ab Januar um zu sparen. www.srf.ch/news/schweiz...
Reposted by Christian Grefe
European particle physics strategy update summary 😅
December 12, 2025 at 4:08 PM
European particle physics strategy update summary 😅
Reposted by Christian Grefe
The European Strategy for Particle Physics reaches an important milestone
At its 225th session, the #CERN Council received the recommendations for the update of the European Strategy for Particle Physics.
Read more: home.cern/news/press-r...
At its 225th session, the #CERN Council received the recommendations for the update of the European Strategy for Particle Physics.
Read more: home.cern/news/press-r...
December 12, 2025 at 2:27 PM
The European Strategy for Particle Physics reaches an important milestone
At its 225th session, the #CERN Council received the recommendations for the update of the European Strategy for Particle Physics.
Read more: home.cern/news/press-r...
At its 225th session, the #CERN Council received the recommendations for the update of the European Strategy for Particle Physics.
Read more: home.cern/news/press-r...
Die neue europäische Strategie für Teilchenphysik erwähnt erstmals explizit die Notwendigkeit für langfristige Verträge um die Expertise von Ingenieuren, Technikern und Physikern, insbesondere für Beschleuniger- und Detektorbau und Betrieb, und Computing im Feld zu erhalten. #IchBinHanna
Outreach, diversity and career aspects are now also mentioned explicitly in the recommendations.
December 12, 2025 at 2:24 PM
Die neue europäische Strategie für Teilchenphysik erwähnt erstmals explizit die Notwendigkeit für langfristige Verträge um die Expertise von Ingenieuren, Technikern und Physikern, insbesondere für Beschleuniger- und Detektorbau und Betrieb, und Computing im Feld zu erhalten. #IchBinHanna
The 2026 Update of the European Strategy for Particle #physics has been released today. It defines a list of priorities and recommendations for the coming decades. This document has been drafted by the Strategy Group and still has to be officially approved by the CERN Council in May 2026. 🧪⚛️
December 12, 2025 at 2:02 PM
The 2026 Update of the European Strategy for Particle #physics has been released today. It defines a list of priorities and recommendations for the coming decades. This document has been drafted by the Strategy Group and still has to be officially approved by the CERN Council in May 2026. 🧪⚛️
Reposted by Christian Grefe
It's not just social media. Looks like visitors to the US from Europe and other countries that are part of the visa waiver program will have to submit an enormous amount of data about themselves and their families, including DNA, if proposed new rules are accepted
December 12, 2025 at 12:24 PM
It's not just social media. Looks like visitors to the US from Europe and other countries that are part of the visa waiver program will have to submit an enormous amount of data about themselves and their families, including DNA, if proposed new rules are accepted
Reposted by Christian Grefe
Alte eigene Aufsätze lesen und sich wundern, was man vor 10 Jahren einmal wusste.
December 6, 2025 at 10:36 AM
Alte eigene Aufsätze lesen und sich wundern, was man vor 10 Jahren einmal wusste.
Speaking of low standards. Die Empfehlung des Schweizer Bundesamtes für Gesundheit ist mindestens 2 alkoholfreie Tage pro Woche??? 🤯
December 3, 2025 at 7:45 AM
Speaking of low standards. Die Empfehlung des Schweizer Bundesamtes für Gesundheit ist mindestens 2 alkoholfreie Tage pro Woche??? 🤯
Reposted by Christian Grefe
![Comic. Panels up to the 10-year point are grayed out. New panels since the Ten Years comic, which chronicles the first ten years of PERSON 1's journey with cancer: (1) [two people in bed] PERSON 1 (woman): One more chapter? PERSON 2 (man): Don’t we both have to get up early? PERSON 1: Nnnnnggggh PERSON 2: Sure, good point. (2) [many people wearing masks, walking while looking at graphs on their phones] (3) [birds landing on people] PERSON 2 in beanie and scarf: Hah! They like *my* seeds best. PERSON 1 in scarf holding phone with a bird sitting on it: Wait, how do I take a picture of this one? (4) [two people rowing boats with tree landscape] (5) [Person 1 carries overflowing stack of things to Person 2 in bed] PERSON 1: I brought you honey lemon tea, more pillows, a cinnamon roll, Tylenol, another blanket, a– PERSON 2: It was just Appendicitis, I’m really– PERSON 1: *It is my turn to take care of you and I am going to do it right!* (6) [Two people in car] (7) [still in car) PERSON 1: Oh my god. PERSON 2: Oh my god. (8) [car driving] PERSON 1: Pull over! PERSON 2: I am! (9) [both people get out of car] (10) [Large colored panel of aurora borealis over water with both people looking on] (11) [Person 1 sits against tree while Person 2 lies on the ground] PERSON 1: Fifteen years. No sign of the cancer. (12) I *am* having some weird symptoms. Joint pain. Fatigue. I think I’m losing my close-up vision. PERSON 2: Yeah. Me too. (13) PERSON 2: I think we’re getting old. (14) PERSON 1: I guess that’s okay. PERSON 2: It’s all I wanted.](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:cz73r7iyiqn26upot4jtjdhk/bafkreihwhjblp5lyiwp63ouar7ocfea7evmckytoeo7rkfuoo4gw5rnrra@jpeg)
November 26, 2025 at 10:32 PM
Reposted by Christian Grefe
Liebe "PiA - Physik im Advent" FreundInnen, nur noch 10 Tage bis zum
Start von "PiA - Physik im Advent". JETZT anmelden:
www.physik-im-advent.de Bitte informiert auch Eure FreundInnen,
Lehrkäfte, Nachbarn ... #Physik #MINT #Bildung
#DigitaleBildung #Adventskalender #Advent #Schule #Lehrer
Start von "PiA - Physik im Advent". JETZT anmelden:
www.physik-im-advent.de Bitte informiert auch Eure FreundInnen,
Lehrkäfte, Nachbarn ... #Physik #MINT #Bildung
#DigitaleBildung #Adventskalender #Advent #Schule #Lehrer
November 21, 2025 at 4:10 PM
Liebe "PiA - Physik im Advent" FreundInnen, nur noch 10 Tage bis zum
Start von "PiA - Physik im Advent". JETZT anmelden:
www.physik-im-advent.de Bitte informiert auch Eure FreundInnen,
Lehrkäfte, Nachbarn ... #Physik #MINT #Bildung
#DigitaleBildung #Adventskalender #Advent #Schule #Lehrer
Start von "PiA - Physik im Advent". JETZT anmelden:
www.physik-im-advent.de Bitte informiert auch Eure FreundInnen,
Lehrkäfte, Nachbarn ... #Physik #MINT #Bildung
#DigitaleBildung #Adventskalender #Advent #Schule #Lehrer
Reposted by Christian Grefe
Happy #PrideinSTEMDay! 🏳️🌈🏳️⚧️
ATLAS proudly celebrates the incredible diversity of our scientific community. Our varied backgrounds, perspectives and identities drive excellence in research. We are committed to advancing the recognition and representation of our LGBTQ+ colleagues — today and every day.
ATLAS proudly celebrates the incredible diversity of our scientific community. Our varied backgrounds, perspectives and identities drive excellence in research. We are committed to advancing the recognition and representation of our LGBTQ+ colleagues — today and every day.
November 18, 2025 at 3:08 PM
Happy #PrideinSTEMDay! 🏳️🌈🏳️⚧️
ATLAS proudly celebrates the incredible diversity of our scientific community. Our varied backgrounds, perspectives and identities drive excellence in research. We are committed to advancing the recognition and representation of our LGBTQ+ colleagues — today and every day.
ATLAS proudly celebrates the incredible diversity of our scientific community. Our varied backgrounds, perspectives and identities drive excellence in research. We are committed to advancing the recognition and representation of our LGBTQ+ colleagues — today and every day.
Reposted by Christian Grefe
Es geht wieder los mit der Reform des #WissZeitVG! Der letzte Versuch ist geplatzt, weil die 🚦 auseinandergeflogen ist. Aber: Seitdem liegen aussichtsreiche Lösungen für das Kernproblem Postdoc-Phase auf dem Tisch! Wie lassen sich Befristungen in dieser Phase eindämmen? 5 Instrumente: ⬇️ #IchBinHanna
Wird Zeit fürs WissZeitVG: Auf ein Neues!
Die Reform-Debatte nimmt wieder an Fahrt auf -- Grund genug, uns aussichtsreiche Lösungen für die Kernproblematik der Postdoc-Phase ins Gedächtnis zu rufen!
steady.page
November 18, 2025 at 8:11 AM
Es geht wieder los mit der Reform des #WissZeitVG! Der letzte Versuch ist geplatzt, weil die 🚦 auseinandergeflogen ist. Aber: Seitdem liegen aussichtsreiche Lösungen für das Kernproblem Postdoc-Phase auf dem Tisch! Wie lassen sich Befristungen in dieser Phase eindämmen? 5 Instrumente: ⬇️ #IchBinHanna
Reposted by Christian Grefe
Heavy-ion season is here! 💥
The ATLAS Experiment at @cern.bsky.social has recorded its first lead-lead collisions of 2025, marking the start of three weeks of heavy-ion running at 5.36 TeV per nucleon pair. Take a look at some of our first spectacular event displays!
The ATLAS Experiment at @cern.bsky.social has recorded its first lead-lead collisions of 2025, marking the start of three weeks of heavy-ion running at 5.36 TeV per nucleon pair. Take a look at some of our first spectacular event displays!
November 18, 2025 at 9:55 AM
Heavy-ion season is here! 💥
The ATLAS Experiment at @cern.bsky.social has recorded its first lead-lead collisions of 2025, marking the start of three weeks of heavy-ion running at 5.36 TeV per nucleon pair. Take a look at some of our first spectacular event displays!
The ATLAS Experiment at @cern.bsky.social has recorded its first lead-lead collisions of 2025, marking the start of three weeks of heavy-ion running at 5.36 TeV per nucleon pair. Take a look at some of our first spectacular event displays!
Reposted by Christian Grefe
Es geht wieder los mit der Reform des #WissZeitVG! Diesmal muss es was werden, faire Bedingungen überfällig: Was ich 2023 gesagt habe, gilt weiterhin! ⬇️ @drkeichhorn.bsky.social, @kubon.bsky.social & ich haben uns in der letzten Runde intensiv für #IchBinHanna eingesetzt, werden’s auch diesmal tun.💪
November 17, 2025 at 6:04 PM
Es geht wieder los mit der Reform des #WissZeitVG! Diesmal muss es was werden, faire Bedingungen überfällig: Was ich 2023 gesagt habe, gilt weiterhin! ⬇️ @drkeichhorn.bsky.social, @kubon.bsky.social & ich haben uns in der letzten Runde intensiv für #IchBinHanna eingesetzt, werden’s auch diesmal tun.💪
Reposted by Christian Grefe
![Comic. [Person with ponytail pointing at diagram while speaking to three other people] PERSON: If the emergency stop is activated, any riders on the waterslide will be diverted into the beam dump, a large graphite block which will safely absorb their momentum. [caption] We regretted hiring an accelerator physicist to design our water park.](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:cz73r7iyiqn26upot4jtjdhk/bafkreicnzdnpjdz4clfa2uhx6isbdwgu72oku5pee4av7paavbjmqpyoiu@jpeg)
November 18, 2025 at 3:40 AM
Reposted by Christian Grefe
Students, apply for a CERN summer studentship. Greatest experience ever!
Deadline 26 January 2026. careers.cern/programmes/s...
(It's not just for physicists. Check it out.)
Deadline 26 January 2026. careers.cern/programmes/s...
(It's not just for physicists. Check it out.)
Summer Studentship
Programme overview Join the CERN Summer Student Programme and dive into cutting-edge research. You’ll work on advanced scientific and technical projects, contributing directly to CERN’s…
careers.cern
November 15, 2025 at 3:24 PM
Students, apply for a CERN summer studentship. Greatest experience ever!
Deadline 26 January 2026. careers.cern/programmes/s...
(It's not just for physicists. Check it out.)
Deadline 26 January 2026. careers.cern/programmes/s...
(It's not just for physicists. Check it out.)
Last part of the 2025 LHC physics programme has just started. We will take 3 weeks of heavy ion collision data before going to a short end of year break in December.
November 14, 2025 at 2:59 PM
Last part of the 2025 LHC physics programme has just started. We will take 3 weeks of heavy ion collision data before going to a short end of year break in December.
Was fun to see so many friends and colleagues on the big screen 😃 Not sure when and where "the peace particle" movie will be screened for a wider audience, but I can definitely recommend it.
November 13, 2025 at 10:00 PM
Was fun to see so many friends and colleagues on the big screen 😃 Not sure when and where "the peace particle" movie will be screened for a wider audience, but I can definitely recommend it.