At first glance this NASA/ESA Hubble Space Telescope image seems to show an array of different cosmic objects, but the speckling of stars shown here actually forms a single body — a nearby dwarf galaxy known as Leo A. Its few million stars are so sparsely distributed that some distant background galaxies are visible through it.
Earth does not always spin on an axis running through its poles. Instead, it wobbles irregularly over time, currently drifting toward the British Isles at 17cm per year. These wobbles don’t affect our daily life, but they must be taken into account to get accurate results from GPS, satellites and observatories on the ground.
In a global exoplanet observation experiment, NASA’s Kepler K2 mission and Earth-based observatories on six continents hope to survey millions of stars toward the centre of our Milky Way galaxy. Using a technique called gravitational microlensing, scientists will hunt for exoplanets that orbit far from their host star and for free-floating exoplanets that wander between the stars.
Brown dwarfs are objects that are too large to be called planets, yet too small to shine by nuclear fusion. Two German researchers have taken a careful look at the distribution of nearby examples of these “failed stars” and to their surprise discovered a significant asymmetry in their spatial arrangement.
Several recent news stories have reported that a mysterious anomaly in the orbit of NASA’s Cassini spacecraft around Saturn could potentially be explained by the gravitational tug of theorised Planet 9, existing far beyond the orbit of Neptune in our solar system. However, NASA cannot find any unexplained deviations in the spacecraft’s orbit.
Exoplanet KELT-4Ab, about one and a half times the size of Jupiter, orbits the main star of a three-star system every three days. The system’s other two stars orbit each other once every 30 years while simultaneously orbiting the main star — and the planet — once every 4,000 years. The triple star system lies about 685 light-years from Earth.
Sprawling across Pluto’s icy landscape is an unusual geological feature that resembles a giant spider. This enhanced colour image, obtained by NASA’s New Horizons spacecraft on 14 July 2015, consists of at least six extensional fractures (arrowed) converging to a point near the centre. Curiously, the spider’s “legs” expose red deposits below Pluto’s surface.
A near-record 17-billion-solar-mass black hole discovered in a sparse area of the local universe indicates that these monster objects may be more common than once thought. The newly discovered supermassive black hole is in NGC 1600, an elliptical galaxy in the constellation Eridanus some 149 million light-years away.
An international team of scientists has found radioactive iron-60 in sediment and crust samples taken from the Pacific, Atlantic and Indian Oceans. They report that a series of massive supernova explosions occurring between 3.2 and 1.7 million years ago from stars less than 300 light-years away showered the Earth with radioactive debris.
© 2019 Pole Star Publications Limited