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In addition, FARSIDE would provide a pathfinder for power spectrum measurements of the Dark Ages. Angiogenesis inhibitor This article is part of a discussion meeting issue 'Astronomy from the Moon the next decades'.This work sketches a possible design architecture of a low-frequency radio interferometer located on the lunar surface. The design has evolved from single antenna experiments aimed at the global signal detection of the epoch of reionization (EoR) to the square kilometre array (SKA) which, when complete, will be capable of imaging the highly red-shifted H1-signal from the cosmic dawn through to the EoR. However, due to the opacity of the ionosphere below 10 MHz and the anthropogenic radio-frequency interference, these terrestrial facilities are incapable of detecting pre-ionization signals and the moon becomes an attractive location to build a low-frequency radio interferometer capable of detecting such cosmological signals. Even though there are enormous engineering challenges to overcome, having this scientific facility on the lunar surface also opens up several new exciting possibilities for low-frequency radio astronomy. This article is part of a discussion meeting issue 'Astronomy from the Moon the next decades'.Infrared astronomy, particularly in spectroscopy, could benefit in a decisive way from an implementation of telescopes on the Moon since the largest telescopes on Earth are practically limited to 40 m and in space to 10 m. On the Moon, a collector larger than on Earth becomes conceivable, thanks to the low gravity and the absence of wind, in having the advantages of space. Passively cooled in the bottom of a permanently shadowed crater at the northern or the southern pole, it could reach unprecedented spectral sensitivity on a large part of the infrared domain, making possible spectral analysis of the most primitive galaxies and of the terrestrial exoplanet atmospheres. link2 A project aiming at the detection of the weak cosmic microwave background spectral distortions is also presented. Several identical 1.5 m cryo-cooled telescopes at 2.5 K to fit in a launcher, with an imaging Fourier transform spectrometer in each unit, deposited in a cold crater and pointing in the same direction in lunar survey mode, would build for this fundamental goal the equivalent of a large telescope at an extremely low temperature. Last, the feasibility of these projects is discussed. This article is part of a discussion meeting issue 'Astronomy from the Moon the next decades'.The lunar surface allows a unique way forward in cosmology, to go beyond current limits. The far side provides an unexcelled radio-quiet environment for probing the dark ages via 21 cm interferometry to seek elusive clues on the nature of the infinitesimal fluctuations that seeded galaxy formation. Far-infrared telescopes in cold and dark lunar polar craters will probe back to the first months of the Big Bang and study associated spectral distortions in the CMB. Optical and IR megatelescopes will image the first star clusters in the Universe and seek biosignatures in the atmospheres of unprecedented numbers of nearby habitable zone exoplanets. The goals are compelling and a stable lunar platform will enable construction of telescopes that can access trillions of modes in the sky, providing the key to exploration of our cosmic origins. This article is part of a discussion meeting issue 'Astronomy from the Moon the next decades'.The lunar surface has been exposed to the space environment for billions of years and during this time has accumulated records of a wide range of astrophysical phenomena. These include solar wind particles and the cosmogenic products of solar particle events which preserve a record of the past evolution of the Sun, and cosmogenic nuclides produced by high-energy galactic cosmic rays which potentially record the galactic environment of the Solar System through time. The lunar surface may also have accreted material from the local interstellar medium, including supernova ejecta and material from interstellar clouds encountered by the Solar System in the past. Owing to the Moon's relatively low level of geological activity, absence of an atmosphere, and, for much of its history, lack of a magnetic field, the lunar surface is ideally suited to collect these astronomical records. Moreover, the Moon exhibits geological processes able to bury and thus both preserve and 'time-stamp' these records, although gaining access to them is likely to require a significant scientific infrastructure on the lunar surface. This article is part of a discussion meeting issue 'Astronomy from the Moon the next decades'.Following earlier proposals for optical stellar interferometer concepts in space and on the Moon, the improved 'hypertelescope' version capable of direct high-resolution imaging with a high limiting magnitude became tested on Earth, proposed for space, and is now also proposed for the Moon. Many small mirrors can be dilutely arrayed in a lunar impact crater spanning 10-25 km. And a larger version, modified for a flat lunar site and spanning up to several hundred kilometres can be built later if needed for a higher resolution and limiting magnitude. Even larger versions, at the scale of many thousand kilometres, also appear feasible in space at some stage, in the form of a controlled flotilla of mirrors. Among the varied science targets considered with the imaging resolution expected, reaching 100 nano-arcseconds on the Moon, are (a) the early detection and resolved imaging of Near Earth Objects, and their monitoring for eventual collision avoidance by orbital deflection; (b) multi-pixel imaging of exoplanets as part of the search for exolife by mapping local seasonal spectral variations; (c) the physics of neutron stars and black holes at the galactic centre and in other Active Galactic Nuclei; and (d) distant galaxies of cosmological interest. This article is part of a discussion meeting issue 'Astronomy from the Moon the next decades'.A 20 m space telescope is described with an unvignetted 1° field of view-a hundred times larger in area than fields of existing space telescopes. Its diffraction-limited images are a hundred times sharper than from wide-field ground-based telescopes and extend over much if not all the field, 40 arcmin diameter at 500 nm wavelength, for example. The optical system yielding a 1°, 1.36 m diameter image at f/3.9 has relatively small central obscuration, 9% by area on axis, and is fully baffled. Several carousel-mounted instruments can each access directly the full image. The initial instrument complement includes a 400 gigapixel silicon imager with 2 µm pixels (0.005 arcsec), and a 60 gigapixel HgCdTe imager with 5 µm pixels (0.012 arcsec). A multi-object spectrograph with 10 000 fibres will allow spectroscopy with 0.02 arcsec resolution. Direct imaging and spectroscopy of exoplanets can take advantage of the un-aberrated, on-axis image (5 nm RMS wavefront error). While this telescope could be built for operation in free space, a site accessible to a human outpost at the Moon's south pole would be advantageous, for assembly and repairs. The lunar site would allow also for the installation of new instruments to keep up with evolving scientific priorities and advancing technology. Cooling to less than 100E K would be achieved with a surrounding cylindrical thermal shield. This article is part of a discussion meeting issue 'Astronomy from the Moon the next decades'.The initial conditions for the density perturbations in the early Universe, which dictate the large-scale structure and distribution of galaxies we see today, are set during inflation. Measurements of primordial non-Gaussianity are crucial for distinguishing between different inflationary models. Current measurements of the matter power spectrum from the cosmic microwave background only constrain this on scales up to k ∼ 0.1 Mpc-1. Reaching smaller angular scales (higher values of k) can provide new constraints on non-Gaussianity. A powerful way to do this is by measuring the HI matter power spectrum at [Formula see text]. In this paper, we investigate what values of k can be reached for the Low-Frequency Array (LOFAR), which can achieve [Formula see text]1″ resolution at approximately 50 MHz. Combining this with a technique to isolate the spectrally smooth foregrounds to a wedge in [Formula see text]-k⊥ space, we demonstrate what values of k we can feasibly reach within observational constraints. We find that LOFAR is approximately five orders of magnitude away from the desired sensitivity, for 10 years of integration time. This article is part of a discussion meeting issue 'Astronomy from the Moon the next decades'.We describe a polar Moon base habitat using direct solar energy for construction, food production and atmospheric revitalization. With a growing area as large as 2000 m2, it could provide for 40 or more people. The habitat is built like the ancient Roman Pantheon, a stone structure with a top circular oculus, bringing in focused sunlight that is spread out to crops below. The conical, corbelled structure is built from cast regolith blocks, held in compression despite the large internal atmospheric pressure by a regolith overlayer 20-30 m thick. It is sealed on the inside against leaks with thin plastic. A solar mirror concentrator used initially to cast the building blocks is later used to illuminate the habitat through a small pressure window at the oculus. Three years of robotic preparation of the building blocks does not seem excessive for a habitat which can be expected to last for millennia, as has the Treasury of Atreus made by similar dry-stone construction. One goal of returning to the Moon is to demonstrate the practicality of long-term human habitation off the Earth. The off-axis, paraboloidal reflecting mirror is rotated about the vertical polar axis in order to direct horizontal sunlight downward to a focus. In this way, the heavy materials needed from Earth to build and power the habitat are largely limited to the solar concentrator and regolith moving and moulding equipment. By illuminating with a reflector rather than with electricity, the solar collection area is 20 times smaller than would be needed for PV cells. This article is part of a discussion meeting issue 'Astronomy from the Moon the next decades'.There is strong interest in lunar exploration from governmental space agencies, private companies and the public. NASA is about to send humans to the lunar surface again within the next few years, and ESA has proposed the concept of the Moon Village, with the goal of a sustainable human presence and activity on the lunar surface. Although construction of the infrastructure for this permanent human settlement is envisaged for the end of this decade by many, there is no definite mission plan yet. While this may be unsatisfactory for the impatient, this fact actually carries great potential this is the optimal time to develop a forward-looking science input and influence mission planning. Based on data from recent missions (SMART-1, Kaguya, Chang'E, Chandrayaan-1 and LRO) as well as simulation campaigns (e.g. link3 ILEWG EuroMoonMars), we provide initial input on how astronomy could be incorporated into a future Moon Village, and how the presence of humans (and robots) on the Moon could help deploy and maintain astronomical hardware.
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