News tagged with stars

The evidence for pair-instability supernovae

A supernova is a stellar explosion. They can occur when a large star exhausts its ability to fuse hydrogen into higher elements, and its core collapses. The resulting rebound rips apart the outer layers of ...

Oct 06, 2014
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How small can galaxies be?

Yesterday I talked about just how small a star can be, so today let's explore just how small a galaxy can be. Our Milky Way galaxy is about 100,000 light years across, and contains about 200 billion stars. Th ...

Sep 29, 2014
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The coolest stars

One way that stars are categorized is by temperature. Since the temperature of a star can determine its visual color, this category scheme is known as spectral type. The main categories of spectral type are ...

Sep 29, 2014
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Sensitive youngsters

Young individuals of a species are often more sensitive towards environmental stress than their adult counterparts. Scientists from GEOMAR Helmholtz Centre for Ocean Research Kiel now observed this effect in the sea star ...

Sep 26, 2014
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How genes trace life on Earth

A complete tree of life – showing how and when organisms are related to each other – has long been desired by biologists, but obscured by the vagaries of the fossil record. ...

Sep 25, 2014
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Image: NGC 6872 in the constellation of Pavo

This picture, taken by the NASA/ESA Hubble Space Telescope's Wide Field Planetary Camera 2 (WFPC2), shows a galaxy known as NGC 6872 in the constellation of Pavo (The Peacock). Its unusual shape is caused ...

Sep 23, 2014
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Measuring the proper motion of a galaxy

The motion of a star relative to us can be determined by measuring two quantities, radial motion and proper motion. Radial motion is the motion of a star along our line of sight. That is, motion directly ...

Sep 23, 2014
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