Category Astronomy/Space

Backscattered electron images of urban cosmic spherules. Credit: M.J. Genge et al., Geology

More than 100 billion micrometeorites (MMs) fall to Earth each year. Until now, scientists believed that these particles could only be found in the cleanest environments, such as the Antarctic. In their new paper for Geology, M.J. Genge and colleagues show that, contrary to that expectation, micrometeorites can be recovered from city rooftops (eg, primarily in Norway) and that, unlike those from the Antarctic, they are the youngest collected to date.

This is not a new proposition. It has been a popular belief among amateur astronomers that such modern-day extraterrestrial dust can be collected on roofs in urban environments...

The PROCYON spacecraft and comet 67P/Churumov-Gerasiment (Conceptual Image). Credit: NAOJ/ESA/Go Miyazaki

In September 2015, a team of astronomers from the National Astronomical Observatory of Japan, University of Michigan, Kyoto Sangyo University, Rikkyo University and the University of Tokyo successfully observed the entire hydrogen coma of the comet 67P/Churyumov-Gerasimenko, using LAICA telescope onboard the PROCYON spacecraft. They also succeeded in obtaining the absolute rate of water discharge from the comet.

This comet was the target of ESA’s Rosetta mission in 2015. Because the Rosetta spacecraft was actually inside the cometary coma, it couldn’t observe the overall coma structure...

TNT dwarf groups. Three colour images of four of the dwarf groups obtained with the Maryland–Magellan Tunable Filter (MMTF) Fabry Perot (Δλ = 10 Å) for dm1049+09 (top left), dm1349-02 (top right) and dm1623+15 (bottom left), and with the Gemini Multi-Object Spectrograph (Δλ = 50 Å) for dm1719+30 (bottom right). Red corresponds to Hα, green corresponds to MMTF or Gemini r-band, and blue corresponds to SDSS g-band. Velocities derived from optical spectroscopy are noted for each group member.

Dwarf galaxies, nuggets of stars and gas 100 to 1,000 times smaller than the Milky Way, are thought to be the building blocks of massive galaxies. Evidence for groups of merging dwarf galaxies, however, has been lacking, until now...

SEAS researchers suggest that early Mars may have been warmed intermittently by a powerful greenhouse effect, possibly explaining water on the planet’s surface billions of years ago. Credit: NASA

Findings may help in search for life in the universe. The presence of water on ancient Mars is a paradox. There’s plenty of geographical evidence that rivers periodically flowed across the planet’s surface. Yet in the time period when these waters are supposed to have run – 3 to 4 billion years ago – Mars should have been too cold to support liquid water. Researchers from the Harvard John A. Paulson School of Engineering and Applied Science (SEAS) suggest that early Mars may have been warmed intermittently by a powerful greenhouse effect...