Next Week’s Night Sky:
When the moon completes the first quarter of its orbit around Earth at 1:47 p.m. EST (or 18:47 GMT) on Friday, Feb. 19, the relative positions of the Earth, sun, and moon will cause us to see it half-illuminated — on its eastern side. In the first quarter, the moon always rises around noon and sets around midnight, so it is also visible in the afternoon daytime sky. The evenings surrounding the first quarter are the best for seeing the lunar terrain when it is dramatically lit by low-angle sunlight. This first quarter phase will occur while the moon is passing several degrees to the right (celestial north) of the triangular face of Taurus, which is composed of the large Hyades star cluster and the bright foreground star Aldebaran. Look for the bright Pleiades star cluster to the moon’s right.
A Black Hole Swarm
Black holes are thought to range between two extremes: from stellar-mass black holes that form when single, massive stars collapse to the supermassive behemoths millions to billions of times the mass of the Sun. Intermediate-mass holes, with the gravitational heft of hundreds to tens of thousands of stars, are thought to bridge the gap between the two extremes, but only a few candidates have been identified to date.
Likely habitats for intermediate black holes are the cores of globular clusters, the concentrated assemblies of ancient stars that are nearly as old as the cosmos. Researchers using the Hubble Space Telescope observed one of the closest globulars to Earth – NGC 6397 – looking for stellar motions that might indicate the gravitational influence of an intermediate black hole.
Instead, they were surprised to find signs of multiple stellar-mass black holes.
Combining the precision measurements from Hubble with data from the European Space Agency’s Gaia space observatory, the researchers concluded the observed motions are best explained by the remnants of massive objects that sank to the center of the cluster after interactions – dynamical friction – with nearby, less massive stars.
A Hubble Nebula
This image from the NASA/ESA Hubble Space Telescope features an impressive portrait of M1-63, a beautifully captured example of a bipolar planetary nebula located in the constellation of Scutum (the Shield).
A nebula like this one is formed when the star at its center sheds huge quantities of material from its outer layers, leaving behind a spectacular cloud of gas and dust.
It is believed that a binary system of stars at the center of the bipolar nebula is capable of creating hourglass or butterfly-like shapes like the one in this image.
This is because the material from the shedding star is funneled toward its poles, with the help of the companion, creating the distinctive double-lobed structure seen in nebulae such as M1-63.
Young Galaxy Portrait
Scientists have challenged our current understanding of how galaxies form by unveiling pictures of a young galaxy in the early life of the Universe which appears surprisingly mature.
The galaxy, dubbed ALESS 073.1, appears to have all of the features expected of a much more mature galaxy and has led the team of scientists to question how it grew so fast.
The new research has been published today in Science.
Galaxies come in a variety of shapes, sizes and colours, and are made up of different components such as rotating disks, spiral arms, and “bulges”.
A major goal of present-day astronomy is understanding why different galaxies look the way they are today and when their different components formed.
The team, led by scientists at Cardiff University, used the Atacama Large Millimeter/submillimeter Array (ALMA) telescope as a ‘time machine’ to peer into the remote past, revealing how ALESS 073.1 looked just 1.2 billion years after the Big Bang.
Because the light emitted from the galaxy took billions of years to reach our telescopes on Earth, the team were able to explore how the galaxy looked during its infancy and determine how it was initially formed.
The result was one of the sharpest, direct images of a primordial galaxy ever produced which allowed the team to undertake a detailed study of its internal structure.
Do you have any cool astronomy research news from this week? Share it in the comments below!