The Origin of the Universe as Revealed Through the Polarization of the Cosmic Microwave Background

Modern cosmology has sharpened questions posed for millennia about the origin of our cosmic habitat. The age-old questions have been transformed into two pressing issues primed for attack in the coming decade: How did the Universe begin? and What physical laws govern the Universe at the highest energies? The clearest window onto these questions is the pattern of polarization in the Cosmic Microwave Background (CMB), which is uniquely sensitive to primordial gravity waves. A detection of the special pattern produced by gravity waves would be not only an unprecedented discovery, but also a direct probe of physics at the earliest observable instants of our Universe. Experiments which map CMB polarization over the coming decade will lead us on our first steps towards answering these age-old questions.Comment: Science White Paper submitted to the US Astro2010 Decadal Survey. Full list of 212 author available at http://cmbpol.uchicago.ed

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]

GOCE SSTI L2 tracking losses and their impact on POD performance

The state-of-the-art GOCE Satellite-to-Satellite Tracking Instrument (SSTI) delivers high-quality GPS data with an almost continuous 1 Hz data rate, which allows for very Precise Orbit Determination (POD). Despite this good performance, the GPS receiver shows occasional unexpected L2 tracking losses, which mainly occur close to the geomagnetic poles and, to a lesser extent, also along the geomagnetic equator. The number of unexpected L2 tracking losses varies in time and shows some correlation with solar activity. Less than 3% of the observation data is affected by these losses. Therefore, the effect on the POD remains limited. However, systematic effects might be present, as the quality of the GOCE orbits is slightly reduced over the polar regions. The striking correlation between the global distribution of ionospheric irregularities and L2 losses suggests scintillation effects might be present. Analysis of the time derivative of the geometry-free combination of GPS phase observations shows that unexpected L2 losses occur during times of rapid ionospheric fluctuations. GPS satellites in cross-track direction are most affected by L2 losses.Space EngineeringAerospace Engineerin

Tracking and orbit determination performance of the GRAS instrument on MetOp-A

The global navigation satellite system receiver for atmospheric sounding (GRAS) on MetOp-A is the first European GPS receiver providing dual-frequency navigation and occultation measurements from a spaceborne platform on a routine basis. The receiver is based on ESA’s AGGA-2 correlator chip, which implements a high-quality tracking scheme for semi-codeless P(Y) code tracking on the L1 and L2 frequency. Data collected with the zenith antenna on MetOp-A have been used to perform an in-flight characterization of the GRAS instrument with focus on the tracking and navigation performance. Besides an assessment of the receiver noise and systematic measurement errors, the study addresses the precise orbit determination accuracy achievable with the GRAS receiver. A consistency on the 5 cm level is demonstrated for reduced dynamics orbit solutions computed independently by four different agencies and software packages. With purely kinematic solutions, 10 cm accuracy is obtained. As a part of the analysis, an empirical antenna offset correction and preliminary phase center correction map are derived, which notably reduce the carrier phase residuals and improve the consistency of kinematic orbit determination results.Delft Institute of earth Observation and Space SystemsAerospace Engineerin

Challenges with sea ice action on structures for Offshore wind

EU urgently needs to increase the development of secure and green energy, and this includes renewables such as Offshore wind energy. An expansion of Offshore wind will include the Baltic where sea ice is one of the major uncertainties. To ensure that the w ind turbines are safe for people and the environment, while keeping them economically competitive better guidelines and regulations should b e developed collaboratively by European industry and academia. There are unsolved challenge s with respect to ice action on structures for offshore wind. However, in the current draft for Horizon Europe Work Programme 2023-2024 on Climate, Energy and Mobility1, the challenges related to sea ice with regards to Offshore wind energy are not mentioned. In order to meet the crucial green energy goals, it is our statement that it is imperative to include sea ice i n the final version.Offshore Engineerin

Observing the Evolution of the Universe

How did the universe evolve? The fine angular scale (l>1000) temperature and polarization anisotropies in the CMB are a Rosetta stone for understanding the evolution of the universe. Through detailed measurements one may address everything from the physics of the birth of the universe to the history of star formation and the process by which galaxies formed. One may in addition track the evolution of the dark energy and discover the net neutrino mass. We are at the dawn of a new era in which hundreds of square degrees of sky can be mapped with arcminute resolution and sensitivities measured in microKelvin. Acquiring these data requires the use of special purpose telescopes such as the Atacama Cosmology Telescope (ACT), located in Chile, and the South Pole Telescope (SPT). These new telescopes are outfitted with a new generation of custom mm-wave kilo-pixel arrays. Additional instruments are in the planning stages

The Origin of the Universe as Revealed Through the Polarization of the Cosmic Microwave Background

Modern cosmology has sharpened questions posed for millennia about the origin of our cosmic habitat. The age-old questions have been transformed into two pressing issues primed for attack in the coming decade: How did the Universe begin? and What physical laws govern the Universe at the highest energies? The clearest window onto these questions is the pattern of polarization in the Cosmic Microwave Background (CMB), which is uniquely sensitive to primordial gravity waves. A detection of the special pattern produced by gravity waves would be not only an unprecedented discovery, but also a direct probe of physics at the earliest observable instants of our Universe. Experiments which map CMB polarization over the coming decade will lead us on our first steps towards answering these age-old questions