This image, taken with the Wide Field Planetary Camera 2 on board the NASA/ESA Hubble Space Telescope, shows the globular cluster Terzan 1. Lying around 20,000 light-years from us in the constellation of Scorpius (The Scorpion), it is one of about 150 globular clusters belonging to our galaxy, the Milky Way.
Typical globular clusters are collections of around a hundred thousand stars, held together by their mutual gravitational attraction in a spherical shape a few hundred light-years across. It is thought that every galaxy has a population of globular clusters. Some, like the Milky Way, have a few hundred, while giant elliptical galaxies can have several thousand.
They contain some of the oldest stars in a galaxy, hence the reddish colors of the stars in this image — the bright blue ones are foreground stars, not part of the cluster. The ages of the stars in the globular cluster tell us that they were formed during the early stages of galaxy formation! Studying them can also help us to understand how galaxies formed.
Terzan 1, like many globular clusters, is a source of X-rays. It is likely that these X-rays come from binary star systems that contain a dense neutron star and a normal star. The neutron star drags material from the companion star, causing a burst of X-ray emission. The system then enters a quiescent phase in which the neutron star cools, giving off X-ray emission with different characteristics, before enough material from the companion builds up to trigger another outburst.
Source: NASA press release
The potential discovery of a planet orbiting Barnard’s Star – the second closest stellar system to the Sun – was announced by researchers today in Nature.
In the past thirty years, the number of planets discovered beyond our Solar System has grown exponentially. Unfortunately, due to the limitations of our technology, the vast majority of these exoplanets have been discovered by indirect means, often by detecting the transits of planets in front of their stars (the Transit Method) or by the gravitational influence they exert on their star (the Radial Velocity Method)
Imagine trying to map out your home town using only information you could gather from your window. Even with a pair of binoculars you’d find it a difficult task. Mapping out our own galaxy, the Milky Way, is a similarly daunting mission. Unlike other galaxies that we can view from a distance, we sit inside the Milky Way – around 26,000 light years from its center. This means that when we try to look at the opposite side of the galaxy, much of our view is blocked by the stars and dust in between.
In December of 2013, the European Space Agency (ESA) launched the Gaia mission. Since that time, this space observatory has been busy observing over 1 billion astronomical objects in our galaxy and beyond – including stars, planets, comets, asteroids, quasars, etc. – all for the sake of creating the largest and most precise 3D space catalog ever made.
In Star Wars VI we first meet the Ewoks living on the Forest Moon of Endor. The planet Endor itself is a gas giant, but the Forest Moon is a habitable world, peopled by small furry sentient creatures. While we may not be living in the Star Wars universe, astronomers have now found the first evidence for a moon orbiting a gas giant planet in a star system other than our own.
The Big Bang was the explosion that started it all. Explosions have centers. Therefore our universe has a center, right? Well, no. Not exactly.
Ever since astronauts began going to space for extended periods of time, it has been known that long-term exposure to zero-gravity or microgravity comes with its share of health effects. These include muscle atrophy and loss of bone density, but also extend to other areas of the body leading to diminished organ function, circulation, and even genetic changes.
In of August of 2016, astronomers from the European Southern Observatory (ESO) confirmed the existence of an Earth-like planet around Proxima Centauri – the closest star to our Solar System. In addition, they confirmed that this planet (Proxima b) orbited within its star’s habitable zone. Since that time, multiple studies have been conducted to determine if Proxima b could in fact be habitable.
Over the past few decades, the number of extra-solar planets that have been detected and confirmed has grown exponentially. At present, the existence of 3,778 exoplanets have been confirmed in 2,818 planetary systems, with an additional 2,737 candidates awaiting confirmation. With this volume of planets available for study, the focus of exoplanet research has started to shift from detection towards characterization.
We might just get that Moon base Elon Musk is hoping for