Volume 1 Issue 2, February 2017

We have found many Earth-sized worlds but we have no way of determining if their surfaces are Earth-like. This makes it impossible to quantitatively compare habitability, and pretending we can risks damaging the field.

As scientists, the terminology we choose influences our thinking as it carries our messages to colleagues and the public. In the face of pressure to turn science into clickbait, maintaining precision in the language we use is critical to dispel misinformation and, more broadly, to enable scientific progress.

The discovery of groups of dwarf galaxies in extremely isolated environments provides direct observational evidence of hierarchical assembly at small galactic scales.

The motion of the Local Group is due to the gravitational pull of nearby concentrations of galaxies and clusters — superclusters — but the push from a giant underdense region may be just as important.

Measurements now show that the distribution of meteorite compositions arriving to Earth was significantly different in the past and that the flux changes on short timescales.

Our currently accepted model of a hierarchically growing, dark-matter dominated Universe predicts rare isolated groups of dwarf galaxies. The discovery of seven such systems may point to the building blocks of present-day intermediate-mass galaxies.

Periodic pulsations of polarized emission and a strong magnetic field were found in a white-dwarf double system. These findings confirm a pulsar-like emission mechanism for the system that has so far been associated only with neutron stars.

Heck et al. provide the first experimental evidence that the composition of meteorites falling on the Earth changes with time. The distribution of meteorites 470 million years ago is significantly different from today — an effect linked to events happening in the asteroid belt.

The authors present evidence that the lunar soil contains oxygen ions from Earth that escape our atmosphere and reach the Moon through the Earth’s magnetospheric wind. The lunar surface possibly contains clues about the history of Earth’s atmosphere.

Isotopic analyses of stardust have yet to single out a specific stellar origin for it. A revision of the proton-capture rate of ¹⁷O has helped to identify intermediate mass stars (4–8 solar masses) as the source of a large fraction of meteoritic stardust.

The New Horizons spacecraft revealed a large dark reddish area along Pluto’s equatorial region, probably made up by organics. Here the authors show that it could be formed by the very same giant impact that created Pluto’s biggest satellite, Charon.

The presence of a large underdensity, the dipole repeller, is predicted based on a study of the velocity field of our Local Group of galaxies. The combined effects of this super-void and the Shapley concentration control the local cosmic flow.

Using a radio telescope with no moving parts, the dark energy speeding up the expansion of the Universe can be probed in unprecedented detail, says Keith Vanderlinde, on behalf of the CHIME collaboration.