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The Australian Astronomical Observatory operates the Anglo-Australian Telescope and the United Kingdom Schmidt Telescope in Australia, as well as coordinating access for the Australian community to the Gemini, Magellan, and other…
Reliable forecasts of the Earth system are crucial for human progress and safety from natural disasters. Artificial intelligence offers substantial potential to improve prediction accuracy and computational efficiency in this field, however…
The new astronomical technique of gravitational microlensing enables measurements of high precision to be made in certain circumstances. Useful advances have been made in the fields of galactic astronomy, stellar astronomy and planetary…
High-contrast observations in optical and infrared astronomy are defined as any observation requiring a technique to reveal a celestial object of interest that is in such close angular proximity to another source brighter by a factor of at…
Imagining what life on other planets, and intelligent life in particular, may be like is a long-running theme in human culture. It is a manifestation of the innate human curiosity about the Cosmos, and it has inspired numerous works of art…
In wildfires, burning pieces of ember-firebrands-are carried downstream by wind. At the time of landing, these firebrands can start secondary fires far away from the main burning unit. This phenomenon is called spotting and the secondary…
We recently presented evidence of a strong correlation between the energy in the high-frequency part of the acoustic spectrum of the Sun and the solar X-ray flux Karoff & Kjeldsen (2008). The discovery indicates that flares drive global…
Galaxies are lighthouses that sit atop peaks in the density field. There is good observational evidence that these lighthouses do not provide a uniform description of the distribution of dark matter.
The most remarkable feature of the ultraviolet auroras at Jupiter is the ever present and almost continuous curtain of bright emissions centered on each magnetic pole and called the main emissions. According to the classical theory, it…
We describe how cosmology has converged towards a beautiful model of the Universe: the Big Bang Universe. We praise this model, but show there is a dark side to it. This dark side is usually called ``the cosmological problems'': a set of…
Dark matter (DM) comes from long-range gravitational observations, and it is considered as something that does not interact with ordinary matter or emits light. However, also on much smaller scales, a number of unexpected observations of…
Astronomical light echoes, the time-dependent light scattered by dust in the vicinity of varying objects, have been recognized for over a century. Initially, their utility was thought to be confined to mapping out the three-dimensional…
The recent results of the Pierre Auger Observatory on the possible correlation of Ultra High Energy Cosmic Rays events and several nearby discrete sources could be the starting point of a new era with charged particles astronomy. In this…
Cultural astronomy is an interdisciplinary area of research that studies how perceptions and concepts related to the sky are part of the worldview of a culture. One of its branches, archaeoastronomy, focuses on the material remains of past…
While low latitude auroral displays are normally considered to be a manifestation of magnetic storms of considerable size, Silverman (2003, JGR, 108, A4) reported numerous "sporadic auroras" which appear locally at relatively low magnetic…
The first observations of Saturn's visible-wavelength aurora were made by the Cassini camera. The aurora was observed between 2006 and 2013 in the northern and southern hemispheres. The color of the aurora changes from pink at a few hundred…
Observations of intensely bright star-forming galaxies both close by and in the distant Universe at first glance seem to emphasize their similarity. But look a little closer, and differences emerge.
The origin of cosmic rays is one of the major unresolved questions in astrophysics. In particular, the highest energy cosmic rays observed possess macroscopic energies and their origin is likely associated with the most energetic processes…
We carefully consider numerous explanations for the sulfur abundance anomaly in planetary nebulae. No one rationale appears to be satisfactory, and we suggest that the ultimate explanation is likely to be a heretofore unidentified feature…
The most distant -ray burst yet sighted is the earliest astronomical object ever observed in cosmic history. This ancient beacon offers a glimpse of the little-known cosmic dark ages.