Category Astronomy/Space

White dwarf stars in the early Milky Way. Credit: NASA, ESA, A. Calamida and K. Sahu (STScI), and the SWEEPS Science Team; Credit for Ground-based Image: A. Fujii

Peering deep into the Milky Way’s crowded central hub of stars, Hubble researchers have uncovered for the 1st time a population of ancient white dwarfs, smoldering remnants of once-vibrant stars that inhabited the core. This can yield clues to how our galaxy was built, long before Earth/sun formed.

The white dwarfs contain information about the stars that existed about 12 billion years ago that burned out to form the white dwarfs. As these dying embers of once-radiant stars cool, they serve as multi-billion-year-old time pieces that tell astronomers about the Milky Way’s groundbreaking years.

An analysis of the Hubble data suppor...

Mars Express aurora detections

Mars Express has for the 1st time combined remote observations with in situ measurements of electrons hitting the atmosphere. On Earth, auroras are often-spectacular light shows at high northern and southern polar latitudes as the solar wind interacts with Earth’s magnetic field. As charged atomic particles from the Sun are drawn along Earth’s magnetic field, they collide with different molecules and atoms in the atmosphere to create dynamic, colourful curtains and rays in the sky.

These light displays are also found on other planets, including those with powerful magnetic fields such as Jupiter and Saturn. But they can even occur on planets with no magnetic field, such as Venus and Mars.
In the absence of a global magnetic field, solar particles can directly...

NASA’s GRACE satellites (artist’s concept) measured Atlantic Ocean bottom pressure as an indicator of deep ocean current speed. In 2009, this pattern of above-average (blue) and below-average (red) seafloor pressure revealed a temporary slowing of the deep currents. Credits: NASA/JPL-Caltech

A team of NASA and university scientists has developed a new way to use satellite measurements to track changes in Atlantic Ocean currents, which are a driving force in global climate. The finding opens a path to better monitoring and understanding of how ocean circulation is changing and what the changes may mean for future climate.

In the Atlantic, currents at the ocean surface, eg Gulf Stream, carry sun-warmed water from the tropics NE. As the water moves through colder regions, it sheds its heat...

Radar images received by the Green Bank Telescope reveal new details of the surface of asteroid 2015 TB145. Credit: NASA/JPL-Caltech/GSSR/NRAO/AUI/NSF

Scientists used the 230-foot DSS-14 antenna at Goldstone, California, to transmit high-power microwaves toward the asteroid. The signal bounced off the asteroid, and its radar echoes were received by the National Radio Astronomy Observatory’s (NRAO) 100-meter (330-foot) Green Bank Telescope in West Virginia. The radar images achieve a spatial resolution as fine as 13 ft/ pixel, an amazing feat.

The radar images were taken as the asteroid flew past Earth on October 31 at 1 p.m. EDT at about 1.3 lunar distances (300,000 miles, or 480,000 kilometers) from Earth. Asteroid 2015 TB145 is spherical in shape and approximately 2,000 feet in diameter.