Liquid Oxygen Is Magnetic

Chemistry/Physics: Even more smoke tricks

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What is a protostar?

The formation of stars begins with the collapse and fragmentation of molecular clouds into very dense clumps.  These clumps initially contain ~0.01 solar masses of material, but increase in mass as surrounding material is accumulated through accretion.  The temperature of the material also increases while the area over which it is spread decreases as gravitational contraction continues, forming a more stellar-like object in the process.  During this time, and up until hydrogen burning begins and it joins the main sequence, the object is known as a protostar.

This stage of stellar evolution may last for between 100,000 and 10 million years depending on the size of the star being formed. If the final result is a protostar with more than 0.08 solar masses, it will go on to begin hydrogen burning and will join the main sequence as a normal star.  For protostars with masses less than this, temperatures are not sufficient for hydrogen burning to begin and they become brown dwarf stars.

Protostars are enshrouded in gas and dust and are not detectable at visible wavelengths.  To study this very early stage of stellar evolution, astronomers must use infrared or microwave wavelengths.

Protostars are also known as Young Stellar Objects (YSOs).

The Magellanic Clouds are two irregular dwarf galaxies visible in the Southern Celestial Hemisphere; they are members of the Local Group and are orbiting the Milky Way galaxy. Because they both show signs of a bar structure, they are often reclassified as Magellanic spiral galaxies. The two galaxies are:

Large Magellanic Cloud (LMC), approximately 160,000 light-years away.

Small Magellanic Cloud (SMC), approximately 200,000 light years away.

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Image credit: Primoz Cigler, Joseph Brimacombe, Ed Dunens and EkantTakePhotos

Coal Sack & Carina Nebulae - Stirling Ranges, Western Australia

SNR 0509-67.5: a remnant from a supernova in the Large Magellanic Cloud

Credit: NASA/ESA/Hubble Team/Kevin M. Gill

If Earth had Saturn’s Rings

From an excellent post by Jason Davis

From Washington, D.C., the rings would only fill a portion of the sky, but appear striking nonetheless. Here, we see them at sunrise.

From Guatemala, only 14 degrees above the equator, the rings would begin to stretch across the horizon. Their reflected light would make the moon much brighter.

From Earth’s equator, Saturn’s rings would be viewed edge-on, appearing as a thin, bright line bisecting the sky.

At the March and September equinoxes, the Sun would be positioned directly over the rings, casting a dramatic shadow at the equator.

At midnight at the Tropic of Capricorn, which sits at 23 degrees south latitude, the Earth casts a shadow over the middle of the rings, while the outer portions remain lit.

via x

The First Real Photo Of Entire Earth From Apollo 8 In 1968.