20151228 - astronomical milestones

 

Astronomical milestones of 2015

Magazine issue: Vol. 188, No. 13, December 26, 2015, p. 22

 

The New Horizons mission to Pluto might get all the attention, but 2015 had plenty of other amazing space mission firsts — and lasts, as scientists said good-bye to two orbiters.

Dawn

The Dawn probe arrived at Ceres March 6, becoming the first spacecraft to orbit a dwarf planet (take that, Pluto!) (SN: 4/4/15, p. 9). Dawn quickly started mapping its new home. Bright patches sitting within craters (SN Online: 9/10/15), which at first glance looked like exposed ice, are probably salt deposits. The craters themselves are also puzzlingly scattered unevenly across the surface (SN: 9/5/15, p. 8).

Rosetta 

A leak of oxygen, buried since the solar system’s start, was the last thing Rosetta mission researchers expected to detect at comet 67P/Churyumov-Gerasimenko. Finding such oxygen was a first in cometary chemistry (SN: 11/28/15, p. 6). The Philae lander, meanwhile, surprised the world when it awoke June 13 from a nearly seven-month slumber (SN Online: 6/14/15). Contact has since been spotty.

Kepler

NASA’s premier planet hunter introduced us to Kepler 452b this year, possibly the most Earthlike world yet known (SN: 8/22/15, p. 16). Its 385-day orbit of a sunlike star would be comforting to humans. But at 1.6 times the width of Earth, the exoplanet might not have a solid surface on which they could enjoy it. That’s OK. With 1,030 confirmed exoplanets and counting, the Kepler space telescope keeps looking.

 https://www.sciencenews.org/article/astronomical-milestones-2015