Explore the vast range of titles available.

Citizen science covers initiatives from crowdsourcing, distributed intelligence, and participatory science, to extreme citizen science. Terminological overlap, varied project aims, and cultural differences in the fields of research have, however, led to discord regarding how impactful citizen science projects can be. Here, we showcase a mobile application-based citizen science campaign (in Finnish: Muuttolintujen kevät), an automated bird sound classifier of Finnish birds. Over a single season (2023), the method attracted 140,000 participants who uploaded close to three million recordings containing six million bird observations. We report the spatial and temporal distribution of the observations collected, characterize the user behaviour, and discuss reliability of the user-based validations of the AI-powered species identifications. To circumvent data quality problems that characterize many citizen science projects, our approach stores the raw audio in a centralized repository, enabling rigorous validation and re-analysis. Mobile application-based citizen science initiatives can be harnessed to probe the state of our environment almost in real time and potentially guide conservation acts in the future.

We present a summary of the results of the OJ 287 observational campaign, which was carried out during the 2021/2022 observational season. This season is special in the binary model because the major axis of the precessing binary happens to lie almost exactly in the plane of the accretion disc of the primary. This leads to pairs of almost identical impacts between the secondary black hole and the accretion disk in 2005 and 2022. In 2005, a special flare called “blue flash” was observed 35 days after the disk impact, which should have also been verifiable in 2022. We did observe a similar flash and were able to obtain more details of its properties. We describe this in the framework of expanding cloud models. In addition, we were able to identify the flare arising exactly at the time of the disc crossing from its photo-polarimetric and gamma-ray properties. This is an important identification, as it directly confirms the orbit model. Moreover, we saw a huge flare that lasted only one day. We may understand this as the lighting up of the jet of the secondary black hole when its Roche lobe is suddenly flooded by the gas from the primary disk. Therefore, this may be the first time we directly observed the secondary black hole in the OJ 287 binary system.

We compare the performance of four symplectic integration methods with leading order symplectic corrector in simulations of the Solar System. These simulations cover 10 Gyr. They are longer than the astrophysical predicted future of the present-day Solar System, thus this work is mainly a study of the integration methods. For the outer Solar System simulation, where the used stepsize was 100 days, the energy errors do not show any secular evolution. The maximum errors show a dependence on the method. The simulations of the full Solar System from Mercury, and including Pluto as a test particle, were calculated with a stepsize of 7 days. The energy errors behave somewhat differently having a small secular behavior. This may due to the short timestep and the short period of the planet Mercury or some small round off error produced by the code. Comparison of the eccentricity evolution’s within simulations show that some planets are dynamically strongly coupled. Venus and Earth form a dynamical pair, also Jupiter and Saturn form a dynamical pair. The FFT of the analysis of the simulations suggests that all the giant planets form a single dynamical quadruple system. The orbit of Mercury is possibly unstable. Each simulation is stopped when Mercury is expelled. All the methods show similar results for times less than 30Myr in the way that the results for orbital elements are same within plotting precision. Inclusion of Mercury in simulations shortens the Solar System e-folding time to 3.3Myr. It is clear that chaos has a strong effect in the evolution of orbital elements, especially eccentricities. This is easily seen in Mercury’s orbit when the simulation time exceeds at least 30 Myr. Our low-order simulations seem to match high-order methods over long timescales.

Avian pox is a disease caused by Avipoxvirus spp. that is known to produce self-limiting, proliferative epithelial lesions in over 275 bird species from 70 families. Although generally benign, this emerging disease can sometimes provoke significant outbreaks of mortality. In rallids, there is a single serological record of Avipoxvirus. In this study, we report on field evidence for two avian pox-like outbreaks in Eurasian coots, Fulica atra. In Utterslev Mose, Denmark, 17 birds were found in the winter and early spring of 2006 with putative signs of pox-like lesions on the frontal shield and bill. Similar lesions were detected in a population of c. 30 Eurasian coots from a small wetland in eastern Spain in the winter of 2018. Birds with active lesions were detected up to 73 days after first finding, and percentage of birds with lesions also increased in this period (from 9.1% to 69.6%), then declined. Lesions of individual birds were observed to heal in 2 weeks. Three young coots exhibited severe lesions that hampered breathing. In other 17 wetlands from the same region, pox-like lesions were detected in 8 out of 843 Eurasian coots from three localities (maximum prevalence: 18.8%) and 1 of 8 Crested coots, Fulica cristata, in one locality. Reports from European birdwatchers describing coots with abnormal frontal shields suggest that some of these birds likely suffered also from avian pox. This disease, unnoticed thus far, could be geographically widespread, thus its potential population impact should not be underestimated, especially in Crested coots.

Grains collected from comet 67P/Churyumov-Gerasimenko by the Rosetta mission come from a dusty crust that is predicted to be imminently shed as the comet nears the Sun; the grains are high in sodium and fluffy, not icy, suggesting that they are the precursors of interplanetary dust particles. Rosetta's analysis of cometary dust Since August 2014, the Rosetta spacecraft has been in orbit around comet 67P/Churyumov-Gerasimenko, monitoring the evolution of the comet as it advances towards the Sun. Here Rita Schulz et al . present initial results from Rosetta's COSIMA instrument, which is collecting cometary dust grains for optical and compositional analysis. They describe grains collected from the dusty crust that quenches material outflow at the comet surface. This dust is part of the mantle that is shed as the comet nears the Sun, eventually revealing an icy layer beneath. The larger grains (>50 μm diameter) are fluffy and many have shattered when collected on the target plate, suggesting that they are agglomerates of interplanetary dust particles. Comets are composed of dust and frozen gases. The ices are mixed with the refractory material either as an icy conglomerate 1 , or as an aggregate of pre-solar grains (grains that existed prior to the formation of the Solar System), mantled by an ice layer 2 , 3 . The presence of water-ice grains in periodic comets is now well established 4 , 5 , 6 . Modelling of infrared spectra obtained about ten kilometres from the nucleus of comet Hartley 2 suggests that larger dust particles are being physically decoupled from fine-grained water-ice particles that may be aggregates 7 , which supports the icy-conglomerate model. It is known that comets build up crusts of dust that are subsequently shed as they approach perihelion 8 , 9 , 10 . Micrometre-sized interplanetary dust particles collected in the Earth’s stratosphere and certain micrometeorites are assumed to be of cometary origin 11 , 12 , 13 . Here we report that grains collected from the Jupiter-family comet 67P/Churyumov-Gerasimenko come from a dusty crust that quenches the material outflow activity at the comet surface 14 . The larger grains (exceeding 50 micrometres across) are fluffy (with porosity over 50 per cent), and many shattered when collected on the target plate, suggesting that they are agglomerates of entities in the size range of interplanetary dust particles. Their surfaces are generally rich in sodium, which explains the high sodium abundance in cometary meteoroids 15 . The particles collected to date therefore probably represent parent material of interplanetary dust particles. This argues against comet dust being composed of a silicate core mantled by organic refractory material and then by a mixture of water-dominated ices 2 , 3 . At its previous recurrence (orbital period 6.5 years), the comet’s dust production doubled when it was between 2.7 and 2.5 astronomical units from the Sun 14 , indicating that this was when the nucleus shed its mantle. Once the mantle is shed, unprocessed material starts to supply the developing coma, radically changing its dust component, which then also contains icy grains, as detected during encounters with other comets closer to the Sun 4 , 5 .

With the aim to visualize the span of time since the formation of our Universe we have set up a nature and hiking trail called ‘Time Trek’. The 13.7 km length of the trail corresponds to the age of the Universe, and portrays its history including events important for Earth and life. One kilometre corresponds to a billion years, and one metre to a million years of time. The trek combines astronomical, physical, geological and biological time lines, and presents a holistic view of the history of time. It helps people to comprehend the causal and temporal connections of different phenomena. To the trekker, it offers a concrete experience of the lengths and proportions of different time periods, which otherwise are very difficult to understand.

Surviving of crews during future missions to Mars will depend on reliable and adequate supplies of essential life support materials, i.e. oxygen, food, clean water, and fuel. The most economical and sustainable (and in long term, the only viable) way to provide these supplies on Martian bases is via bio-regenerative systems, by using local resources to drive oxygenic photosynthesis. Selected cyanobacteria, grown in adequately protective containment could serve as pioneer species to produce life sustaining substrates for higher organisms. The very high (95.3 %) CO 2 content in Martian atmosphere would provide an abundant carbon source for photo-assimilation, but nitrogen would be a strongly limiting substrate for bio-assimilation in this environment, and would need to be supplemented by nitrogen fertilizing. The very high supply of carbon, with rate-limiting supply of nitrogen strongly affects the growth and the metabolic pathways of the photosynthetic organisms. Here we show that modified, Martian-like atmospheric composition (nearly 100 % CO 2 ) under various low pressure conditions (starting from 50 mbar to maintain liquid water, up to 200 mbars) supports strong cellular growth. Under high CO 2 / low N 2 ratio the filamentous cyanobacteria produce significant amount of H 2 during light due to differentiation of high amount of heterocysts.

The bright blazar OJ~287 routinely parades high brightness bremsstrahlung flares, which are explained as being a result of a secondary supermassive black hole (SMBH) impacting the accretion disc of a more massive primary SMBH in a binary system. The accretion disc is not rigid but rather bends in a calculable way due to the tidal influence of the secondary. Below we refer to this phenomenon as a variable disc level. We begin by showing that these flares occur at times predicted by a simple analytical formula, based on general relativity inspired modified Kepler equation, which explains impact flares since 1888. The 2022 impact flare, namely flare number 26, is rather peculiar as it breaks the typical pattern of two impact flares per 12-year cycle. This is the third bremsstrahlung flare of the current cycle that follows the already observed 2015 and 2019 impact flares from OJ~287. It turns out that the arrival epoch of flare number 26 is sensitive to the level of primary SMBH's accretion disc relative to its mean level in our model. We incorporate these tidally induced changes in the level of the accretion disc to infer that the thermal flare should have occurred during July-August 2022, when it was not possible to observe it from the Earth. Thereafter, we explore possible observational evidence for certain pre-flare activity by employing spectral and polarimetric data from our campaigns in 2004/05 and 2021/22. We point out theoretical and observational implications of two observed mini-flares during January-February 2022.

R AQUARII is a symbiotic binary system surrounded by a complex extended optical nebulosity 1 . At radio and optical wavelengths a jet is seen to emerge from the central binary system 2,3 . We have observed R Aqr using the Very Large Array. Comparison with earlier radio observations shows that five out of six bright components in the radio jet have moved. One radio component has the same proper motion as the optical Mira, the primary star of the binary. At a distance of 200 pc (refs 1,4), the proper motions of the other components correspond to a tangential velocity of 44 to 160 km s -l with respect to the Mira. By combining these measurements with radial velocity determinations, we obtain a true three-dimensional velocity map of the radio jet, provided only that the observed proper motions indeed correspond to physical motions of emitting material. Our results rule out the possibility that the radio components in the jet were formed in a single explosive event, and suggest instead that they are 'bullets' ejected at ∼20-yr intervals into a narrow cone. Alternatively, if the components move along the jet and are accelerated during the whole of their passage through the inner 7 arcsec (1,400 AU) of the system, ejection at ∼40-yr intervals would lead to the disposition observed at present.

NINE globular clusters are known to contain luminous (L x > 10 36 erg s −1 ) X-ray sources, but because the X-ray position error boxes, a few arcseconds in size, contain many stars, optical iden-tification of the sources has not been possible, with the exception of that in NGC7078 (ref. 19). This has prevented detailed investiga-tion of the emitting objects. If the X-ray sources are similar to low-mass X-ray binaries (LMXBs) outside globular clusters, low-level radio emission would be expected 1,2 , and the detection of such radio emission would both strengthen the case that luminous globular cluster X-ray sources are LMXBs and aid optical iden-tification by means of an accurate radio position. We report here the detection of radio emission from the position of the luminous X-ray source A1850–08 (ref. 3) in the globular cluster NGC6712. The centroid of the slightly elongated radio source coincides with a previously suggested 20th magnitude stellar optical counterpart 4 . If the radio emission is synchrotron radiation, the minimum energy requirement and magnetic field strength are similar to what is found in the radio counterparts to other high-luminosity X-ray sources such as Sco X-l and Cyg X-3.