̽��ֱ�� of Cambridge - Institute of Astronomy

Strongest hints yet of biological activity outside the solar system

sc604 — Thu, 17 Apr 2025 04:09:34 +0000

Astronomers have detected the most promising signs yet of a possible biosignature outside the solar system, although they remain cautious.

Farewell, Gaia: spacecraft operations come to an end

sc604 — Thu, 27 Mar 2025 10:27:38 +0000

On 27 March 2025, Gaia’s control team at ESA’s European Space Operations Centre switched off the spacecraft’s subsystems and sent it into a ‘retirement orbit’ around the Sun.

Though the spacecraft’s operations are now over, the scientific exploitation of Gaia’s data has just begun.

Launched in 2013, Gaia has transformed our understanding of the cosmos by mapping the positions, distances, motions, and properties of nearly two billion stars and other celestial objects. It has provided the largest, most precise multi-dimensional map of our galaxy ever created, revealing its structure and evolution in unprecedented detail.

̽��ֱ��mission uncovered evidence of past galactic mergers, identified new star clusters, contributed to the discovery of exoplanets and black holes, mapped millions of quasars and galaxies, and tracked hundreds of thousands of asteroids and comets. ̽��ֱ��mission has also enabled the creation of the best visualisation of how our galaxy might look to an outside observer.

“ ̽��ֱ��data from the Gaia satellite has and is transforming our understanding of the Milky Way, how it formed, how it has evolved and how it will evolve,” said Dr Nicholas Walton from Cambridge’s Institute of Astronomy, lead of the Gaia UK project team. “Gaia has been in continuous operation for over 10 years, faultless, without interruption, reflecting the quality of the engineering, with significant elements of Gaia designed and built in the UK. But now it is time for its retirement. Gaia has finished its observations of the night sky. But the analysis of the Gaia mission data continues. Later in 2026 sees the next Gaia Data Release 4, to further underpin new discovery unravelling the beauty and mystery of the cosmos.”

Gaia far exceeded its planned lifetime of five years, and its fuel reserves are dwindling. ̽��ֱ��Gaia team considered how best to dispose of the spacecraft in line with ESA’s efforts to responsibly dispose of its missions.

They wanted to find a way to prevent Gaia from drifting back towards its former home near the scientifically valuable second Lagrange point (L2) of the Sun-Earth system and minimise any potential interference with other missions in the region.

“Switching off a spacecraft at the end of its mission sounds like a simple enough job,” said Gaia Spacecraft Operator Tiago Nogueira. “But spacecraft really don’t want to be switched off.

“We had to design a decommissioning strategy that involved systematically picking apart and disabling the layers of redundancy that have safeguarded Gaia for so long, because we don’t want it to reactivate in the future and begin transmitting again if its solar panels find sunlight.”

On 27 March, the Gaia control team ran through this series of passivation activities. One final use of Gaia’s thrusters moved the spacecraft away from L2 and into a stable retirement orbit around the Sun that will minimise the chance that it comes within 10 million kilometres of Earth for at least the next century.

̽��ֱ��team then deactivated and switched off the spacecraft’s instruments and subsystems one by one, before deliberately corrupting its onboard software. ̽��ֱ��communication subsystem and the central computer were the last to be deactivated.

Gaia’s final transmission to ESOC mission control marked the conclusion of an intentional and carefully orchestrated farewell to a spacecraft that has tirelessly mapped the sky for over a decade.

Though Gaia itself has now gone silent, its contributions to astronomy will continue to shape research for decades. Its vast and expanding data archive remains a treasure trove for scientists, refining knowledge of galactic archaeology, stellar evolution, exoplanets and much more.

“No other mission has had such an impact over such a broad range of astrophysics. It continues to be the source of over 2,000 peer-reviewed papers per year, more than any other space mission,” said Gaia UK team member Dr Dafydd Wyn Evans, also from the Institute of Astronomy. “It is sad that its observing days are over, but work is continuing in Cambridge, and across Europe, to process and calibrate the final data so that Gaia will still be making its impact felt for many years in the future.”

A workhorse of galactic exploration, Gaia has charted the maps that future explorers will rely on to make new discoveries. ̽��ֱ��star trackers on ESA’s Euclid spacecraft use Gaia data to precisely orient the spacecraft. ESA’s upcoming Plato mission will explore exoplanets around stars characterised by Gaia and may follow up on new exoplanetary systems discovered by Gaia.

̽��ֱ��Gaia control team also used the spacecraft’s final weeks to run through a series of technology tests. ̽��ֱ��team tested Gaia’s micro propulsion system under different challenging conditions to examine how it had aged over more than ten years in the harsh environment of space. ̽��ֱ��results may benefit the development of future ESA missions relying on similar propulsion systems, such as the LISA mission.

̽��ֱ��Gaia spacecraft holds a deep emotional significance for those who worked on it. As part of its decommissioning, the names of around 1500 team members who contributed to its mission were used to overwrite some of the back-up software stored in Gaia’s onboard memory.

Personal farewell messages were also written into the spacecraft’s memory, ensuring that Gaia will forever carry a piece of its team with it as it drifts through space.

As Gaia Mission Manager Uwe Lammers put it: “We will never forget Gaia, and Gaia will never forget us.”

̽��ֱ��Cambridge Gaia DPAC team is responsible for the analysis and generation of the Gaia photometric and spectro-photometric data products, and it also generated the Gaia photometric science alert stream for the duration of the satellite's in-flight operations.

Adapted from a media release by the European Space Agency.

̽��ֱ��European Space Agency’s Gaia spacecraft has been powered down, after more than a decade spent gathering data that are now being used to unravel the secrets of our home galaxy.

ESA/Gaia/DPAC, Stefan Payne-Wardenaar

Artist's impression of the Milky Way

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

Yes

Licence type:

Attribution-ShareAlike

Students from across the country get a taste of studying at Cambridge at the Cambridge Festival

zs332 — Thu, 27 Mar 2025 10:17:46 +0000

We were delighted to welcome pupils from Warrington’s Lymm High School, Ipswich High School, ̽��ֱ��Charter School in North Dulwich, Rickmansworth School, Sutton Valance School in Maidstone as well as schools closer to home such as St Peter’s Huntingdon, Fenstanton Primary School, Barton Primary School, Impington Village College and St Andrews School in Soham.

Running over two days (25/26 March 2025) and held in the Cambridge Sports Centre, students went on a great alien hunt with Dr Matt Bothwell from the Institute of Astronomy, stepped back in time to explore Must Farm with Department of Archaeology and the Cambridge Archaeological Unit as well as learning to disagree well with Dr Elizabeth Phillips from ̽��ֱ��Woolf Institute.

Schools had a choice of workshops from a range of departments including, how to think like an engineer and making sustainable food with biotechnology with researchers from the Department of Chemical Engineering and Biotechnology, as well as the chance to get hands-on experience in the world of materials science and explore how properties of materials can be influenced by temperature at the Department of Materials Science and Metallurgy.

̽��ֱ��Department of Veterinary Medicine offered students the opportunity to find out what a career in veterinary medicine may look like with workshops on animal x-rays, how different professionals work together to treat animals in a veterinary hospital as well as meeting the departments horses and cows and learn how veterinarians diagnose and treat these large animals.

Students also had the opportunity to learn about antibodies and our immune system with the MRC Toxicology Unit. ̽��ֱ��students learnt about the incredible job antibodies do defending our bodies against harmful invaders like bacteria and viruses.

Alongside this, a maths trail, developed by Cambridgeshire County Council, guided students around the West Cambridge site whilst testing their maths skills with a number of problems to solve.

Now in their third year, the Cambridge Festival schools days are offering students the opportunity to experience studying at Cambridge with a series of curriculum linked talks and hands on workshops.

̽��ֱ��Cambridge Festival runs from 19 March – 4 April and is a mixture of online, on-demand and in-person events covering all aspects of the world-leading research happening at Cambridge. ̽��ֱ��public have the chance to meet some of the researchers and thought-leaders working in some of the pioneering fields that will impact us all.

Over 500 KS2 and KS3 students from as far away as Warrington got the chance to experience studying at the ̽��ֱ�� of Cambridge with a selection of lectures and workshops held as part of the Cambridge Festival.

Students make antibody keychains during a workshop with the MRC Toxicology Unit

Yes

Cambridge Festival celebrates pioneering women for International Women’s Day

zs332 — Fri, 07 Mar 2025 10:28:52 +0000

For International Women’s Day (8 March), the Cambridge Festival (19 March – 4 April) is celebrating some of the remarkable contributions of women across diverse fields. From philosophy and music to AI and cosmology, the festival will highlight the pioneering work of women who have shaped our understanding of the world in profound ways.

Cambridge Festival Speaker Spotlight: Professor Hiranya Peiris

zs332 — Thu, 06 Mar 2025 16:49:17 +0000

Hiranya Peiris holds the Professorship of Astronomy (1909) at Cambridge, the first woman to do so in the 115-year history of this prestigious chair. As a cosmologist, she delves into cosmic mysteries at the edge of our understanding, reaching back to the very first moments of the Universe after the Big Bang, often treading the path of high risk and high reward.

Cambridge Festival Speaker Spotlight: Dr Matt Bothwell

zs332 — Wed, 12 Feb 2025 13:59:24 +0000

Dr Matthew Bothwell is an astrophysicist, science communicator and author, and the current Public Astronomer at the Institute of Astronomy, ̽��ֱ�� of Cambridge. Part of Matt’s work is to deliver outreach to schools, run stargazing evenings, give public lectures, and write about all things astronomical. He is also a Bye-Fellow at Girton College, ̽��ֱ�� of Cambridge.

Scientists reveal structure of 74 exocomet belts orbiting nearby stars

Anonymous — Fri, 17 Jan 2025 08:00:00 +0000

̽��ֱ��crystal-clear images show light being emitted from these millimetre-sized pebbles within the belts that orbit 74 nearby stars of a wide variety of ages – from those that are just emerging to those in more mature systems like our own Solar System.

̽��ֱ��REASONS (REsolved ALMA and SMA Observations of Nearby Stars) study, led by Trinity College Dublin and involving researchers from the ̽��ֱ�� of Cambridge, is a milestone in the study of exocometary belts because its images and analyses reveal where the pebbles, and the exocomets, are located. They are typically tens to hundreds of astronomical units (the distance from Earth to the Sun) from their central star.

In these regions, it is so cold (-250 to -150 degrees Celsius) that most compounds are frozen as ice on the exocomets. What the researchers are therefore observing is where the ice reservoirs of planetary systems are located. REASONS is the first programme to unveil the structure of these belts for a large sample of 74 exoplanetary systems. ̽��ֱ��results are reported in the journal Astronomy & Astrophysics.

This study used both the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile and the Submillimeter Array (SMA) in Hawai‘i to produce the images that have provided more information on populations of exocomets than ever before. Both telescope arrays observe electromagnetic radiation at millimetre and submillimetre wavelengths.

“Exocomets are boulders of rock and ice, at least one kilometre in size, which smash together within these belts to produce the pebbles that we observe here with the ALMA and SMA arrays of telescopes,” said lead author Luca Matrà from Trinity College Dublin. “Exocometary belts are found in at least 20% of planetary systems, including our own Solar System.”

“ ̽��ֱ��images reveal a remarkable diversity in the structure of belts,” said co-author Dr Sebastián Marino from the ̽��ֱ�� of Exeter. “Some are narrow rings, as in the canonical picture of a ‘belt’ like our Solar System’s Edgeworth-Kuiper belt. But a larger number of them are wide, and probably better described as ‘disks’ rather than rings.”

Some systems have multiple rings/disks, some of which are eccentric, providing evidence that yet undetectable planets are present and their gravity affects the distribution of pebbles in these systems.

“ ̽��ֱ��power of a large study like REASONS is in revealing population-wide properties and trends,” said Matrà.

For example, the study confirmed that the number of pebbles decreases for older planetary systems as belts run out of larger exocomets smashing together, but showed for the first time that this decrease in pebbles is faster if the belt is closer to the central star. It also indirectly showed – through the belts’ vertical thickness – that objects as large as 140 km across and even Moon-size objects are likely present in these belts.

“We have been studying exocometary belts for decades, but until now only a handful had been imaged,” said co-author Professor Mark Wyatt from Cambridge’s Institute of Astronomy. “This is the largest collection of such images and demonstrates that we already have the capabilities to probe the structures of the planetary systems orbiting a large fraction of the stars near to the Sun.”

“Arrays like the ALMA and SMA used in this work are extraordinary tools that are continuing to give us incredible new insights into the universe and its workings,” said co-author Dr David Wilner from the Center for Astrophysics | Harvard & Smithsonian “ ̽��ֱ��REASONS survey required a large community effort and has an incredible legacy value, with multiple potential pathways for future investigation.”

Reference:
L. Matrà et al. ‘REsolved ALMA and SMA Observations of Nearby Stars. REASONS: A population of 74 resolved planetesimal belts at millimetre wavelengths.’ Astronomy & Astrophysics (2025). DOI: 10.1051/0004-6361/202451397

Adapted from a Trinity College Dublin media release.

An international team of astrophysicists has imaged a large number of exocomet belts around nearby stars, and the tiny pebbles within them.

Luca Matra, Trinity College Dublin, and colleagues

Millimetre continuum images for the REASONS resolved sample of 74 exocomet belts

Yes

Last starlight for ground-breaking Gaia

Anonymous — Wed, 15 Jan 2025 09:22:32 +0000

Launched on 19 December 2013, Gaia’s fuel tank is now approaching empty – it uses about a dozen grams of cold gas per day to keep it spinning with pinpoint precision. But this is far from the end of the mission. Technology tests are scheduled for the weeks ahead before Gaia is moved to its ‘retirement’ orbit, and two massive data releases are tabled for around 2026 and the end of this decade, respectively.

“Today marks the end of science observations and we are celebrating this incredible mission that has exceeded all our expectations, lasting for almost twice its originally foreseen lifetime,” said ESA Director of Science Carole Mundell.

“ ̽��ֱ��treasure trove of data collected by Gaia has given us unique insights into the origin and evolution of our Milky Way galaxy, and has also transformed astrophysics and Solar System science in ways that we are yet to fully appreciate. Gaia built on unique European excellence in astrometry and will leave a long-lasting legacy for future generations.”

“Today marks the last day of science data collection from Gaia, these observations to form part of the final data release,” said Dr Nicholas Walton from Cambridge’s Institute of Astronomy, lead of the UK Gaia Project team and ESA Gaia Science Team member. “Our Gaia team in the UK is now working hard on the incredibly complex data analysis for the upcoming Gaia data releases. These will enable a wealth of new discovery, adding to the science from one of the world’s most productive science discovery machines.”

Gaia delivers best Milky Way map

Gaia has been charting the positions, distances, movements, brightness changes, composition and numerous other characteristics of stars by monitoring them with its three instruments many times throughout the mission.

This has enabled Gaia to deliver on its primary goal of building the largest, most precise map of the Milky Way, showing us our home galaxy like no other mission has done before.

Gaia’s repeated measurements of stellar distances, motions and characteristics are key to performing ‘galactic archeology’ on our Milky Way, revealing missing links in our galaxy’s complex history to help us learn more about our origins. From detecting ‘ghosts’ of other galaxies and multiple streams of ancient stars that merged with the Milky Way in its early history, to finding evidence for an ongoing collision with the Sagittarius dwarf galaxy today, Gaia is rewriting the Milky Way’s history and making predictions about its future.

Warning! More ground-breaking science ahead

̽��ֱ��Gaia scientific and engineering teams are already working on the preparations for Gaia Data Release 4 (DR4), expected in 2026.

“This is the Gaia release the community has been waiting for, and it’s exciting to think this only covers half of the collected data,” said Antonella Vallenari, Deputy Chair of DPAC based at the Istituto Nazionale di Astrofisica (INAF), Astronomical Observatory of Padua, Italy. “Even though the mission has now stopped collecting data, it will be business as usual for us for many years to come as we make these incredible datasets ready for use.”

“Over the next months we will continue to downlink every last drop of data from Gaia, and at the same time the processing teams will ramp up their preparations for the fifth and final major data release at the end of this decade, covering the full 10.5 years of mission data,” said Rocio Guerra, Gaia Science Operations Team Leader based at ESA’s European Space Astronomy Centre (ESAC) near Madrid in Spain.

Gaia’s retirement plan

While today marks the end of science observations, a short period of technology testing now begins. ̽��ֱ��tests have the potential to further improve the Gaia calibrations, learn more about the behaviour of certain technology after ten years in space, and even aid the design of future space missions.

After several weeks of testing, Gaia will leave its current orbit around Lagrange point 2, 1.5 million km from the Earth in the direction away from the Sun, to be put into its final heliocentric orbit, far away from Earth’s sphere of influence. ̽��ֱ��spacecraft will be passivated on 27 March 2025, to avoid any harm or interference with other spacecraft.

Wave farewell to Gaia

During the technology tests Gaia’s orientation will be changed, meaning it will temporarily become several magnitudes brighter, making observations through small telescopes a lot easier (it won’t be visible to the naked eye). A guide to locating Gaia has been set up here, and amateur astronomers are invited to share their observations.

“Gaia will treat us with this final gift as we bid farewell, shining among the stars ahead of its well-earned retirement,” said Uwe Lammers, Gaia Mission Manager.

“It’s a moment to celebrate this transformative mission and thank all of the teams for more than a decade of hard work operating Gaia, planning its observations, and ensuring its precious data are returned smoothly to Earth.”

Adapted from a European Space Agency press release.

̽��ֱ��European Space Agency’s Milky Way-mapper Gaia has completed the sky-scanning phase of its mission, racking up more than three trillion observations of about two billion stars and other objects over the last decade to revolutionise the view of our home galaxy and cosmic neighbourhood.

ESA/Gaia/DPAC, Stefan Payne-Wardenaar

This is a new artist’s impression of our galaxy, the Milky Way, based on data from ESA’s Gaia space telescope.

Yes

Licence type:

Attribution-ShareAlike