Archive

Archive for July, 2014

Silhouettes Of Early Galaxies Reveal Few Seeds For New Stars


An international team of astronomers has discovered that gas around young galaxies is almost barren, devoid of the seeds from which new stars are thought to form—molecules of hydrogen.

Without starlight to see them directly, the team, which includes Dr. Regina Jorgenson of the Institute for Astronomy at the University of Hawaii at Manoa—observed the young galaxies’ outskirts in silhouette.

They searched for telltale signs of hydrogen molecules absorbing the light from background objects called quasars—supermassive black holes sucking in surrounding material—that glow very brightly.

“Previous experiments led us to expect molecules in about 10 of the 90 young galaxies we observed, but we found just one case,” said Associate Professor Michael Murphy from Swinburne University of Technology in Australia. He co-led the study with Jorgenson.

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Small, But Plentiful: How The Faintest Galaxies Illuminated The Early Universe


Astronomers investigating behaviour of the universe shortly after the Big Bang have made a surprising discovery: the properties of the early universe are determined by the smallest galaxies. The team report their findings in a paper published today in the journal Monthly Notices of the Royal Astronomical Society.

Shortly after the Big Bang, the universe was ionised: ordinary matter consisted of hydrogen with its positively charged protons stripped of their negatively charged electrons. Eventually, the universe cooled enough for electrons and protons to combine and form neutral hydrogen. This cool gas will eventually form the first stars in the universe but for millions of years, there are no stars. Astronomers therefore aren’t able to see how the cosmos evolved during these ‘dark ages’ using conventional telescopes. The light returned when newly forming stars and galaxies re-ionised the universe during the ‘epoch of re-ionisation’.

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Martian Salts Must Touch Ice To Make Liquid Water, Study Shows


In chambers that mimic Mars’ conditions, University of Michigan researchers have shown how small amounts of liquid water could form on the planet despite its below-freezing temperatures.

Liquid water is an essential ingredient for life as we know it. Mars is one of the very few places in the solar system where scientists have seen promising signs of it – in gullies down crater rims, in instrument readings, and in Phoenix spacecraft self portraits that appeared to show wet beads on the lander’s leg several years ago.

No one has directly detected liquid water beyond Earth, though. The U-M experiments are among the first to test theories about how it could exist in a climate as cold as Mars’ climate.

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Vesta’s Rocky History


© NASA/JPL - Caltech / UCLA / MPS / DLR / IDA

© NASA/JPL – Caltech / UCLA / MPS / DLR / IDA

Rocks are silent storytellers: because each mineral is created only under certain conditions, they provide insight into the evolution of the body on which they are found. Scientists from the Max Planck Institute for Solar System Research (MPS) in Germany have now begun to tell such a story from the enigmatic dark material discovered on the protoplanet Vesta. Using data from the framing camera aboard NASA’s Dawn spacecraft, the researchers have succeeded for the first time in identifying a mineral component of this material: serpentine. The new discovery puts an end to the discussion about the origin of the dark material: impacts of primitive asteroids must have distributed it on Vesta.

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Hubble To Proceed With Full Search For New Horizons Targets


NASA’s Hubble Space Telescope has been given the go-ahead to conduct an intensive search for a suitable outer solar system object that the New Horizons (NH) spacecraft could visit after the probe streaks though the Pluto system in July 2015.

Hubble observations will begin in July and are expected to conclude in August.

Assuming a suitable target is found at the completion of the survey and some follow-up observations are made later in the year, if NASA approves, the New Horizons’ trajectory can be modified in the fall of 2015 to rendezvous with the target Kuiper Belt object (KBO) three to four years later.

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