August 2018

Jupiter Had Growth Disorders

Researchers of the Universities of Zurich and Bern and of ETH Zurich show how Jupiter was formed. Data collected from meteorites had indicated that the growth of the giant planet had been delayed for two million years. Now the researchers have found an explanation: Collisions with kilometer-sized blocks generated high energy, which meant that in this phase hardly any accretion of gas could take place and the planet could only grow slowly.


Yann Alibert, Julia Venturini et al.: “The formation of Jupiter by hybrid pebble- planetesimal accretion”, Nature Astronomy, 27 August 2018. DOI: 10.1038/s41550-018-0557-2


August 2018

«100 Ways of Thinking» - Scientific festival in the Kunsthalle Zürich

You are here: Dr Joachim Stadel's image at the 100 Ways of Thinking Exhibit

A slice through the invisible Universe of dark matter. We are located at the center of the image, in the Present, and the structures extend around us in all directions. The most distant regions observable by the Euclid satellite form the “edge” here at a radius of 10 billion light years, although the structures continue to extend beyond this. Since light takes 10 billion years to travel from this edge to us at the center, we see that the structure of the Universe has noticeably evolved via Gravitation during this time. It is considerably smoother in the past and the large empty regions, known as voids, are much more prominent at the present. The mission of Euclid is to measure this network-like structure and thereby lift the veil of mystery surrounding the nature of Dark Matter and Dark Energy. These dark “Actors” drive the entire evolution of the Universe, but remain puzzling for our understanding of Physics. The computer simulation which produced this map was run on the Piz Daint supercomputer at CSCS in Lugano, and is the largest and most accurate simulation of the dark matter in the Universe ever performed. Galaxies like the Milky Way, which at this scale would fit in the width of a human hair, live in the dark matter halos (dark brown colour).


August 2018

NASA Lands at UZH

NASA research director Thomas Zurbuchen at his talk at UZH: "Discovering the secrets of the universe is one of the most important activities we could be doing as humans, because it is researching who we are, where we come from." (Image: Fabio Schönholzer)

UZH had the honor of welcoming Thomas Zurbuchen, Associate Administrator for the Science Mission Directorate at NASA. He was able to gain an impression of current aviation and spaceflight projects that are being carried out at the UZH Space Hub, which already is collaborating with NASA and further partners.

Discussed space research together: Christian Schwarzenegger, Vice President Faculty Affairs and Scientific Information at UZH, Michael Schaepman, Vice President Research at UZH, Thomas Zurbuchen, research director at NASA, Yasmine Inauen, International Relations Office UZH, Tanya Gant Ward, Public Affairs Officer of the US embassy in Switzerland, Oliver Ullrich, director of the UZH Space Hub, and Romain Teyssier, professor of computational astrophysics. (Image: Fabio Schönholzer)


June 2018

Euclid STAR Prize 2018 Team Award


Flagship mock galaxy catalog team: Linda Blot, Jorge Carretero, Francisco Castander, Pablo Fosalba, Mischa Knabenhans, Doug Potter, Lucia Pozzetti, Santiago Serrano, Joachim Stadel, Pau Tallada, Romain Teyssier

In a massive coordinated effort, a team of scientists of the Euclid project have worked together over the last year to develop the largest simulated galaxy catalogue ever produced, the so-called “Euclid Flagship” mock galaxy catalogue.


February 2018

A Conversation with Democritus | Ben Moore | TEDxZurich

2500 years ago the Greece and the Mediterranean islands must have been a plentiful and lush environment that enabled time to think. Democritus (and others) realized the world around them was understandable without invoking gods. He speculated that everything was made of tiny 'atomos' (he called them), particles so small that you couldn't see them. He was the first to state that the Milky Way was made of stars like our sun, that the universe contained many planets, some with life, others barren and empty. Ben Moore examines how it may have been possible for Democritus to know all this and Democritus' role in uncovering this complex phenomenon that is now widely understood by philosophy and science. A Professor of Astrophysics at the University of Zurich, Ben’s research is centred on understanding the origin and evolution of the universe and how stars, planets and galaxies form. He enjoys communicating science to the public through different media, including writing, music and art. Ben has recently opened the world’s first cosmic concept store in Zurich called Da Draussen.

Watch the TEDx talk on youtube:

November 2017

A “cosmic snake” reveals the structure of remote galaxies

Two close stellar clumps could not be distinguished without a very high resolution (picture on the left). (Image: UZH)

The formation of stars in distant galaxies is still largely unexplored. For the first time, astronomers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

>>Read the press release here

July 2017

Two of the ICS PhD students were accepted to participate in the Zürich Hackathon, taking place in September 2017. Congratulations to Maria Han Veiga and Aleksandra Sokolowska!

June 2017

Ground-breaking simulation for researching the “dark” cosmos

For the first time, scientists have succeeded in carrying out a cosmological simulation with several trillion particles. The simulation on the CSCS supercomputer Piz Daint provides an important basis for researching the universe with the Euclid satellite, which will be launched into space in 2020.

Euclid Flagship
Image copyright J. Stadel 2017

>> View the 2540px image

A small piece of the Simulation showing the complex formed by the dark matter through the action of gravity and the expansion of the Universe. White regions are the voids and the golden concentrations are the halos, where the density of dark matter is the lowest and highest respectively. These two extremes are delineated and connected by the filaments which are shown here in black. The golden colored dark matter halos host the galaxies in our Universe. The image measures 2.5 billion light years across and our entire Milky Way Galaxy would fit inside of a single golden colored pixel.

Image copyright J. Stadel 2017

>> View the full 5000px image

A slice through the invisible universe of dark matter is shown here extending from the present, located at the centre, to the most distant regions observable by the Euclid satellite, 10 billion light years to the left and right. The mission of Euclid will be to indirectly measure this network-like structure through the effect of gravitational lensing. Since light will have taken 10 billion years to travel from the left and right sides of the image to "us" in the center, we see that the Universe in the past looked considerably smoother, and that the large empty regions, known as voids, are much more prominent at the present.

>> Read the full article in English
>> Read the full article in German

>> Swiss National Supercomputing Centre (CSCS) article
>> Euclid Consortium press release
>> UZH Press Release

May 2017

SNSF Scientific Image Competition

The SNSF Scientific Image Competition encourages researchers working in Switzerland to present their works to the public and the media. In May 2017, the international jury chose four prizewinning images and awarded eleven distinctions. In total, 239 researchers registered 497 entries for the SNSF Scientific Image Competition 2017.
Pawel Biernacki, doctoral student, University of Zurich received a distiction for the category "Video loop."

Formation of the Milky Way, Pawel Biernacki
>>download the video
>>Read more

October 2016

Wie Riesenplaneten entstehen

Junge Planeten werden aus Gas und Staub gebildet. Um herauszufinden, was bei ihrer Geburt genau passiert, simulierten die Astrophysikerin Judit Szulágyi von der ETH Zürich und der UZH-Astrophysiker Lucio Mayer unterschiedliche Szenarien am Schweizer Supercomputerzentrum (CSCS).

Die Simulation zeigt die Entstehung eines jungen Planeten. (Bild: Frederic Masset, ETH Zürich / CSCS).

>>Read more

August 2016

Erste Gravitationswellen bilden sich nach 10 Millionen Jahren

Kollidieren zwei Galaxien, löst die Verschmelzung der zentralen schwarzen Löcher Gravitationswellen aus, die sich wellenartig über das ganze Weltall verbreiten. Ein internationales Forschungsteam mit Beteiligung der Universität Zürich hat errechnet, dass dies etwa 10 Millionen Jahre nach der Verschmelzung der Galaxien passiert – viel schneller als bisher angenommen.

>>Read more

Mar 2016

Illuminating the Universe’s Ignition

Shapiro team reionization simulation from OLCF on Vimeo.

This video shows a snapshot of how hot, ionized gas (bright patches) created by millions of galaxies that clustered in space along the threads of a cosmic web, might have been distributed within a piece of the expanding universe 300 million light-years across today, centered on our Milky Way galaxy, when half the volume was still occupied by cold and neutral gas (dark regions).

Read more »

Dec 2016

Billiards and planet formation
Volker Hoffmann, Simon Grimm, Ben Moore & Joachim Stadel
Institute for Computational Science, University of Zurich.


Rocky Earth-like planets are thought to be the end result of a vast number of gravitational interactions and collisions between smaller bodies.
>>> Read full press release
Dec 2014

The History of the Universe in 24 hours with Ben Moore

Nov 2014


Academia Industry Modeling Week: Programmierter Erfolg
In der Academia Industry Modeling Week haben Doktorierende Lösungen für aktuelle und konkrete Forschungsfragen industrieller Unternehmen gesucht. Die Veranstaltung bot Gelegenheit, untereinander und mit der Industrie Kontakte zu knüpfen. 

Oct 2014

«Aliens sehen ganz anders aus»

Der Astrophysiker Ben Moore veröffentlicht sein zweites populäres Buch. In «Da draussen. Leben auf unserem Planeten und anderswo», erklärt er, wie das Leben auf der Erde entstanden ist, wo es im Universum (intelligentes) Leben geben und wie dieses aussehen könnte. UZH News sprach mit Ben Moore über intelligente Aliens, Delfine und Science-Fiction-Romane. 


Apr 2014
This artist's illustration shows the hypervelocity star cluster HVGC-1 escaping from the supergiant elliptical galaxy M87. HVGC-1 is the first runaway star cluster discovered by astronomers. It is fated to drift through intergalactic space. Credit: David A. Aguilar (CfA)

Entire star cluster thrown out of its galaxy

( —The galaxy known as M87 has a fastball that would be the envy of any baseball pitcher. It has thrown an entire star cluster toward us at more than two million miles per hour. The newly discovered cluster, which astronomers named HVGC-1, is now on a fast journey to nowhere. Its fate: to drift through the void between the galaxies for all time.
"Astronomers have found runaway stars before, but this is the first time we've found a runaway ," says Nelson Caldwell of the Harvard-Smithsonian Center for Astrophysics. Caldwell is lead author on the study, which will be published in The Astrophysical Journal Letters and is available online.

Nov 2011

Asteroid in Sicht

In der Nacht von Dienstag auf Mittwoch wird Asteroid «2005 YU55» an der Erde in einem Abstand von 325'000 Kilometer vorbeisausen. Auswirkungen werden auf der Erde nicht zu spüren sein. Irgendwann in der Zukunft wird es für die Erde aber wieder gefährlich werden, erklärt Ben Moore, Professor für Astrophysik an der Universität Zürich. 

Read the full article on the University of Zurich website:

Sep 2011

Earth-Moon planetary systems: TV coverage

May 2011

How common are Earth-Moon planetary systems?


Our Moon formed via a giant impact between our young Earth and a Mars sized proto-planet over four billion years ago. The material torn from the Earth’s surface during the collision accumulated in orbit and formed our familiar satellite. After its formation the Moon was ten times closer to the Earth than it is today and it has drifted slowly away to its present position. Its early intense gravitationally attraction would have caused tidal waves to pass across the Earth’s surface several times per day which may have influenced the initial development of life. 

pdf Read More

pdf Read the article in The "SonntagsZeitung" 26.06.2011

The full article will be published in the journal Icarus and can be found here:

Sep 2011 UPDATE: TV coverage

August 2010

New model: supermassive black holes arrived early, find UniZH team in a paper on the 26 August issue of "Nature" 

Direct formation of supermassive black holes via multi-scale gas inflows in galaxy mergers

Density map of the gas in the nuclear disk at three different times (columns a b and c). Upper panels: large-scale structure of the disk. Lower panels: zoom-in on the collapsing central cloud.

Previously published models of supermassive black hole formation have struggled to explain the fact that  according to observations of distant quasars  supermassive black holes were already in place less than a billion years after the Big Bang. A new series of numerical simulations from a team led by Lucio Mayer at the University of Zurich with PhD student Simone Callegari also from UniZH,
finds that the conditions for direct collapse into a supermassive black hole can arise naturally on this time scale from mergers between massive protogalaxies.Multi-scale gas inflows give rise to an unstable, massive nuclear gas disk that expands to form a sub-parsec scale gas cloud in only 100,000 years. The cloud undergoes gravitational collapse, which leads to the formation of a massive black hole.

The paper:

UNIZH press release
USA TODAY,+Geography/Towns,+Cities,+Counties/Zurich

January 2010

Bulgeless galaxies with dark matter cores simulated

The picture shows the evolution of the assembly of the dwarf galaxy from high to low redshift.

Until now the origin of bulgeless galaxies and slowly rising rotation curves in low mass galaxies was a major puzzle of the cold dark matter model (CDM) for structure formation. Lucio Mayer and colleagues have performed the first supercomputer simulations that forms a bulgeless galaxy with a realistic rotation curve owing to unprecedented resolution.
The work is described on the journal Nature, issue of January 14, 2010.
"Bulgeless galaxies with dark matter cores simulated" Nature, 463, 203-206, 2010.

The simulation resolves the sites of star formation, giant molecular clouds, and shows that outflows generated by supernovae explosions prevent the formation of a bulge by removing baryonic mass from the center of the dwarf galaxy. Removal is fast enough to generate a rapid expansion of inner dark matter component. The final dark matter profile is thus shallower than that predicted by dark-matter only simulations.

Press release Uni Zurich:


June 2009

Baby Milky Way modeled

Researchers unveil state-of-the-art simulation of galaxy formation


Galaxy Formation in Progress from Science News on Vimeo.

This movie models how a galaxy acquires most of its gas — the raw material for making stars. Red is hot gas, blue shows the cold streams of gas that flow like a river toward the galaxy’s center, and green shows gas that has been stripped out of satellite galaxies and enriched in metal content by supernova explosions.

Found in "Baby Milky Way Modeled" online

Credit: B. Moore, Oscar Agertz and Romain Teyssier/University of Zurich