Category Astronomy/Space

Image from the Sloan Digital Sky Survey of the blue oxygen atmosphere white dwarf SDSS J124043.01+671034.68.

Researchers have discovered a white dwarf star with an atmosphere dominated by oxygen, a type of white dwarf that has been theorized to exist but not identified to date. The finding could challenge the textbook wisdom of single stellar evolution, and provide a critical link to some types of supernovae discovered over the past decade.

As relatively small stars (those <10X the mass of our sun) near the end of their lives, they throw off their outer layers and become white dwarf stars, which are very dense. The high gravity that occurs under such density causes the lighter elements, such as hydrogen or helium, to float to the surface of the star, masking the heavier elements below.

Whi...

This is a conceptual image showing how the size and distribution of raindrops varies within a storm. Blues and greens represent small raindrops that are 0.5-3mm in size. Yellows, oranges, and reds represent larger raindrops that are 4-6mm in size. A storm with a higher ratio of yellows, oranges, and reds will contain more water than a storm with a higher ratio of blues and greens. Credit: Credits: NASA/Goddard

For the 1st time, scientists have 3D snapshots of raindrops and snowflakes around the world from space, thanks to the joint NASA and Japan Aerospace Exploration Agency Global Precipitation Measurement (GPM) mission...

The gravitational effects associated with the presence of the Moon and Sun cause cyclical deformation of the Earth’s mantle and wobbles in its rotation axis. This mechanical forcing applied to the whole planet causes strong currents in the outer core, which is made up of a liquid iron alloy of very low viscosity. Such currents are enough to generate the Earth’s magnetic field. Credit: © Julien Monteux and Denis Andrault

The Earth’s magnetic field permanently protects us from the charged particles and radiation that originate in the Sun. This shield is produced by the geodynamo, the rapid motion of huge quantities of liquid iron alloy in the Earth’s outer core...

ALMA image of the planet-forming disk around the young, Sun-like star TW Hydrae. The inset image (upper right) zooms in on the gap nearest to the star, which is at the same distance as the Earth is from the Sun, suggesting an infant version of our home planet could be emerging from the dust and gas. The additional concentric light and dark features represent other planet-forming regions farther out in the disk. Credit: S. Andrews (Harvard-Smithsonian CfA), ALMA (ESO/NAOJ/NRAO)

New images reveal never-before-seen details in the planet-forming disk around a nearby Sun-like star, including a tantalizing gap at the same distance from the star as the Earth is from the Sun. The disks of dust and gas that surround young stars are the formation sites of planets...