̽��ֱ�� of Cambridge - space

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

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.

‘Inside-out’ galaxy growth observed in the early universe

sc604 — Fri, 11 Oct 2024 09:00:00 +0000

This galaxy is one hundred times smaller than the Milky Way, but is surprisingly mature for so early in the universe. Like a large city, this galaxy has a dense collection of stars at its core but becomes less dense in the galactic ‘suburbs’. And like a large city, this galaxy is starting to sprawl, with star formation accelerating in the outskirts.

This is the earliest-ever detection of inside-out galactic growth. Until Webb, it had not been possible to study galaxy growth so early in the universe’s history. Although the images obtained with Webb represent a snapshot in time, the researchers, led by the ̽��ֱ�� of Cambridge, say that studying similar galaxies could help us understand how they transform from clouds of gas into the complex structures we observe today. ̽��ֱ��results are reported in the journal Nature Astronomy.

“ ̽��ֱ��question of how galaxies evolve over cosmic time is an important one in astrophysics,” said co-lead author Dr Sandro Tacchella from Cambridge’s Cavendish Laboratory. “We’ve had lots of excellent data for the last ten million years and for galaxies in our corner of the universe, but now with Webb, we can get observational data from billions of years back in time, probing the first billion years of cosmic history, which opens up all kinds of new questions.”

̽��ֱ��galaxies we observe today grow via two main mechanisms: either they pull in, or accrete, gas to form new stars, or they grow by merging with smaller galaxies. Whether different mechanisms were at work in the early universe is an open question which astronomers are hoping to address with Webb.

“You expect galaxies to start small as gas clouds collapse under their own gravity, forming very dense cores of stars and possibly black holes,” said Tacchella. “As the galaxy grows and star formation increases, it’s sort of like a spinning figure skater: as the skater pulls in their arms, they gather momentum, and they spin faster and faster. Galaxies are somewhat similar, with gas accreting later from larger and larger distances spinning the galaxy up, which is why they often form spiral or disc shapes.”

This galaxy, observed as part of the JADES (JWST Advanced Extragalactic Survey) collaboration, is actively forming stars in the early universe. It has a highly dense core, which despite its relatively young age, is of a similar density to present-day massive elliptical galaxies, which have 1000 times more stars. Most of the star formation is happening further away from the core, with a star-forming ‘clump’ even further out.

̽��ֱ��star formation activity is strongly rising toward the outskirts, as the star formation spreads out and the galaxy grows. This type of growth had been predicted with theoretical models, but with Webb, it is now possible to observe it.

“One of the many reasons that Webb is so transformational to us as astronomers is that we’re now able to observe what had previously been predicted through modelling,” said co-author William Baker, a PhD student at the Cavendish. “It’s like being able to check your homework.”

Using Webb, the researchers extracted information from the light emitted by the galaxy at different wavelengths, which they then used to estimate the number of younger stars versus older stars, which is converted into an estimate of the stellar mass and star formation rate.

Because the galaxy is so compact, the individual images of the galaxy were ‘forward modelled’ to take into account instrumental effects. Using stellar population modelling that includes prescriptions for gas emission and dust absorption, the researchers found older stars in the core, while the surrounding disc component is undergoing very active star formation. This galaxy doubles its stellar mass in the outskirts roughly every 10 million years, which is very rapid: the Milky Way galaxy doubles its mass only every 10 billion years.

̽��ֱ��density of the galactic core, as well as the high star formation rate, suggest that this young galaxy is rich with the gas it needs to form new stars, which may reflect different conditions in the early universe.

“Of course, this is only one galaxy, so we need to know what other galaxies at the time were doing,” said Tacchella. “Were all galaxies like this one? We’re now analysing similar data from other galaxies. By looking at different galaxies across cosmic time, we may be able to reconstruct the growth cycle and demonstrate how galaxies grow to their eventual size today.”

Reference:
William M. Baker, Sandro Tacchella, et al. ‘A core in a star-forming disc as evidence of inside-out growth in the early Universe.’ Nature Astronomy (2024). DOI: 10.1038/s41550-024-02384-8

Astronomers have used the NASA/ESA James Webb Space Telescope (JWST) to observe the ‘inside-out’ growth of a galaxy in the early universe, only 700 million years after the Big Bang.

NASA, ESA, CSA, Sandro Tacchella, William Baker, Ovee Tulaskar

Galaxy NGC 1549, seen today and possibly 13 billion years ago

Yes

Earliest detection of metal challenges what we know about the first galaxies

sc604 — Thu, 06 Jun 2024 14:52:26 +0000

Using the James Webb Space Telescope (JWST), an international team of astronomers led by the ̽��ֱ�� of Cambridge observed a very young galaxy in the early universe and found that it contained surprising amounts of carbon, one of the seeds of life as we know it.

In astronomy, elements heavier than hydrogen or helium are classed as metals. ̽��ֱ��very early universe was almost entirely made up of hydrogen, the simplest of the elements, with small amounts of helium and tiny amounts of lithium.

Every other element that makes up the universe we observe today was formed inside a star. When stars explode as supernovas, the elements they produce are circulated throughout their host galaxy, seeding the next generation of stars. With every new generation of stars and ‘stardust’, more metals are formed, and after billions of years, the universe evolves to a point where it can support rocky planets like Earth and life like us.

̽��ֱ��ability to trace the origin and evolution of metals will help us understand how we went from a universe made almost entirely of just two chemical elements, to the incredible complexity we see today.

“ ̽��ֱ��very first stars are the holy grail of chemical evolution,” said lead author Dr Francesco D’Eugenio, from the Kavli Institute for Cosmology at Cambridge. “Since they are made only of primordial elements, they behave very differently to modern stars. By studying how and when the first metals formed inside stars, we can set a time frame for the earliest steps on the path that led to the formation of life.”

Carbon is a fundamental element in the evolution of the universe, since it can form into grains of dust that clump together, eventually forming into the first planetesimals and the earliest planets. Carbon is also key for the formation of life on Earth.

“Earlier research suggested that carbon started to form in large quantities relatively late – about one billion years after the Big Bang,” said co-author Professor Roberto Maiolino, also from the Kavli Institute. “But we’ve found that carbon formed much earlier – it might even be the oldest metal of all.”

̽��ֱ��team used the JWST to observe a very distant galaxy – one of the most distant galaxies yet observed – just 350 million years after the Big Bang, more than 13 billion years ago. This galaxy is compact and low mass – about 100,000 times less massive than the Milky Way.

“It’s just an embryo of a galaxy when we observe it, but it could evolve into something quite big, about the size of the Milky Way,” said D’Eugenio. “But for such a young galaxy, it’s fairly massive.”

̽��ֱ��researchers used Webb’s Near Infrared Spectrograph (NIRSpec) to break down the light coming from the young galaxy into a spectrum of colours. Different elements leave different chemical fingerprints in the galaxy’s spectrum, allowing the team to determine its chemical composition. Analysis of this spectrum showed a confident detection of carbon, and tentative detections of oxygen and neon, although further observations will be required to confirm the presence of these other elements.

“We were surprised to see carbon so early in the universe, since it was thought that the earliest stars produced much more oxygen than carbon,” said Maiolino. “We had thought that carbon was enriched much later, through entirely different processes, but the fact that it appears so early tells us that the very first stars may have operated very differently.”

According to some models, when the earliest stars exploded as supernovas, they may have released less energy than initially expected. In this case, carbon, which was in the stars’ outer shell and was less gravitationally bound than oxygen, could have escaped more easily and spread throughout the galaxy, while a large amount of oxygen fell back and collapsed into a black hole.

“These observations tell us that carbon can be enriched quickly in the early universe,” said D’Eugenio. “And because carbon is fundamental to life as we know it, it’s not necessarily true that life must have evolved much later in the universe. Perhaps life emerged much earlier – although if there’s life elsewhere in the universe, it might have evolved very differently than it did here on Earth.”

̽��ֱ��results have been accepted for publication in the journal Astronomy & Astrophysics and are based on data obtained within the JWST Advanced Deep Extragalactic Survey (JADES).

̽��ֱ��research was supported in part by the European Research Council, the Royal Society, and the Science and Technology Facilities Council (STFC), part of UK Research and Innovation (UKRI).

Reference:
Francesco D’Eugenio et al. ‘JADES: Carbon enrichment 350 Myr after the Big Bang.’ Astronomy & Astrophysics (in press). DOI: 10.48550/arXiv.2311.09908

Astronomers have detected carbon in a galaxy just 350 million years after the Big Bang, the earliest detection of any element in the universe other than hydrogen.

NASA, ESA, CSA, STScI, Brant Robertson (UC Santa Cruz), Ben Johnson (CfA), Sandro Tacchella (Cambridge), Phill Cargile (CfA)

Deep field image from JWST

Yes

New instrument to search for signs of life on other planets

Anonymous — Wed, 05 Jun 2024 14:00:00 +0000

̽��ֱ��ANDES instrument will be installed on ESO’s Extremely Large Telescope (ELT), currently under construction in Chile’s Atacama Desert. It will be used to search for signs of life in exoplanets and look for the very first stars. It will also test variations of the fundamental constants of physics and measure the acceleration of the Universe’s expansion.

̽��ֱ�� ̽��ֱ�� of Cambridge is a member institution on the project, which involves scientists from 13 countries. Professor Roberto Maiolino, from Cambridge’s Cavendish Laboratory and Kavli Institute for Cosmology, is ANDES Project Scientist.

Formerly known as HIRES, ANDES is a powerful spectrograph, an instrument which splits light into its component wavelengths so astronomers can determine properties about astronomical objects, such as their chemical compositions. ̽��ֱ��instrument will have a record-high wavelength precision in the visible and near-infrared regions of light and, when working in combination with the powerful mirror system of the ELT, it will pave the way for research spanning multiple areas of astronomy.

“ANDES is an instrument with an enormous potential for groundbreaking scientific discoveries, which can deeply affect our perception of the Universe far beyond the small community of scientists,” said Alessandro Marconi, ANDES Principal Investigator.

ANDES will conduct detailed surveys of the atmospheres of Earth-like exoplanets, allowing astronomers to search extensively for signs of life. It will also be able to analyse chemical elements in faraway objects in the early Universe, making it likely to be the first instrument capable of detecting signatures of Population III stars, the earliest stars born in the Universe.

In addition, astronomers will be able to use ANDES’ data to test if the fundamental constants of physics vary with time and space. Its comprehensive data will also be used to directly measure the acceleration of the Universe’s expansion, one of the most pressing mysteries about the cosmos.

When operations start later this decade, the ELT will be the world’s biggest eye on the sky, marking a new age in ground-based astronomy.

Adapted from an ESO press release.

̽��ֱ��European Southern Observatory (ESO) has signed an agreement for the design and construction of ANDES, the ArmazoNes high Dispersion Echelle Spectrograph.

ESO

Artist's impression of the ANDES instrument

Yes

Licence type:

Attribution

Webb detects most distant black hole merger to date

sc604 — Thu, 16 May 2024 17:34:22 +0000

Astronomers have found supermassive black holes with masses of millions to billions times that of the Sun in most massive galaxies in the local Universe, including in our Milky Way galaxy. These black holes have likely had a major impact on the evolution of the galaxies they reside in. However, scientists still don’t fully understand how these objects grew to become so massive.

̽��ֱ��finding of gargantuan black holes already in place in the first billion years after the Big Bang indicates that such growth must have happened very rapidly, and very early. Now, the James Webb Space Telescope is shedding new light on the growth of black holes in the early Universe.

̽��ֱ��new Webb observations have provided evidence for an ongoing merger of two galaxies and their massive black holes when the Universe was just 740 million years old. ̽��ֱ��system is known as ZS7.

Massive black holes that are actively accreting matter have distinctive spectrographic features that allow astronomers to identify them. For very distant galaxies, like those in this study, these signatures are inaccessible from the ground and can only be seen with Webb.

“We found evidence for very dense gas with fast motions in the vicinity of the black hole, as well as hot and highly ionised gas illuminated by the energetic radiation typically produced by black holes in their accretion episodes,” said lead author Dr Hannah Übler of Cambridge’s Cavendish Laboratory and Kavli Institute for Cosmology. “Thanks to the unprecedented sharpness of its imaging capabilities, Webb also allowed our team to spatially separate the two black holes.”

̽��ֱ��team found that one of the two black holes has a mass that is 50 million times the mass of the Sun. “ ̽��ֱ��mass of the other black hole is likely similar, although it is much harder to measure because this second black hole is buried in dense gas,” said team member Professor Roberto Maiolino, also from the Kavli Institute.

“Our findings suggest that merging is an important route through which black holes can rapidly grow, even at cosmic dawn,” said Übler. “Together with other Webb findings of active, massive black holes in the distant Universe, our results also show that massive black holes have been shaping the evolution of galaxies from the very beginning.”

̽��ֱ��team notes that once the two black holes merge, they will also generate gravitational waves. Events like this will be detectable with the next generation of gravitational wave observatories, such as the upcoming Laser Interferometer Space Antenna (LISA) mission, which was recently approved by the European Space Agency and will be the first space-based observatory dedicated to studying gravitational waves.

This discovery was from observations made as part of the Galaxy Assembly with NIRSpec Integral Field Spectroscopy programme. ̽��ֱ��team has recently been awarded a new Large Programme in Webb’s Cycle 3 of observations, to study in detail the relationship between massive black holes and their host galaxies in the first billion years. An important component of this programme will be to systematically search for and characterise black hole mergers. This effort will determine the rate at which black hole merging occurs at early cosmic epochs and will assess the role of merging in the early growth of black holes and the rate at which gravitational waves are produced from the dawn of time.

These results have been published in the Monthly Notices of the Royal Astronomical Society.

Reference:
Hannah Übler et al. ‘GA-NIFS: JWST discovers an offset AGN 740 million years after the big bang’ Monthly Notices of the Royal Astronomical Society (2024). DOI: 10.1093/mnras/stae943

Adapted from a press release by the European Space Agency.

An international team of astronomers, led by the ̽��ֱ�� of Cambridge, has used the James Webb Space Telescope to find evidence for an ongoing merger of two galaxies and their massive black holes when the Universe was only 740 million years old. This marks the most distant detection of a black hole merger ever obtained and the first time that this phenomenon has been detected so early in the Universe.

Massive black holes have been shaping the evolution of galaxies from the very beginning

Hannah Übler

ESA/Webb, NASA, CSA, J. Dunlop, H. Übler, R. Maiolino, et. al

̽��ֱ��environment of the galaxy system ZS7 from the JWST PRIMER programme as seen by Webb's NIRCam instrument

Yes

Licence type:

Attribution