Galaxy Blazes With New Stars Born From Close Encounter
A compilation of scientific results from The Stratospheric Observatory for Infrared Astronomy, SOFIA, reveal new clues to how stars form and galaxies evolve, and closer to understanding the environment of Europa and its subsurface ocean. The airborne observatory carries a suite of instruments, each sensitive to different properties of infrared light, that gives astronomers insights into the flow of matter in galaxies.
Look at a galaxy, what do you see? Probably lots of stars. Nebulae too. And that’s probably it. A whole bunch of stars and gas in a variety of colorful assortments; a delight to the eye. And buried among those stars, if you looked carefully enough, you might find planets, black holes, white dwarves, asteroids, and all sorts of assorted chunky odds and ends. The usual galactic milieu.
A fountain in a garden pond could shoot a plume of water to roughly three metres in height. By comparison, the famous fountain on Lake Geneva launches a plume of water up to 140m into the air. Now imagine a fountain launched from the centre of a galaxy, with a supermassive black hole acting as the pump. How far do you think this plume would extend? The answer is over 100,000 light years.
One of the greatest challenges of astronomy is locating objects in space that are obscured by the light of nearby, brighter objects. In addition to making extra-solar planets very difficult to directly image, this problem also intrudes on surveys of the local Universe, where astronomers are unable to detect dwarf and isolated galaxies because of all the brighter ones surrounding them.
It is springtime in the Northern hemisphere. Countless buds that have been waiting patiently on the stems and branches of trees and shrubs are now blossoming into life. The cosmic equivalent of this season is the time between a few hundred million and a billion years after the Big Bang. This is when the first stars and galaxies ignited, spewing light into the dark universe.
In the 1980s, scientists started discovering a new class of extremely bright sources of X-rays in galaxies. These sources were a surprise, as they were clearly located away from the supermassive black holes found in the center of galaxies. At first, researchers thought that many of these ultraluminous X-ray sources, or ULXs, were black holes containing masses between about a hundred and a hundred thousand times that of the sun. Later work has shown some of them may be stellar-mass black holes, containing up to a few tens of times the mass of the sun.
Despite thousands of years of research and observation, there is much that astronomers still don’t know about the Milky Way Galaxy. At present, astronomers estimate that it spans 100,000 to 180,000 light-years in diameter and consisting of 100 to 400 billion stars. In addition, for decades, there have been unresolved questions about how the structure of our galaxy evolved over the course of billions of years.
Scientists have a pretty good picture of how the universe formed and evolved – and how it is structured today. This knowledge all fits together nicely as a “standard cosmological model”, which has been able to successfully predict and describe many observational data in the universe. But now and then scientists discover something that threatens to tear down this valuable framework.
Beauty, grace, mystery — this magnificent spiral galaxy has all the qualities of a perfect galactic Valentine. Captured by the NASA/ESA Hubble Space Telescope, the galaxy NGC 3344 presents itself face-on, allowing astronomers a detailed look at its intricate and elegant structure. And Hubble’s ability to observe objects over a wide range of different wavelengths reveals features that would otherwise remain invisible.
Using the NASA/ESA Hubble Space Telescope, astronomers have discovered that the brightest galaxies within galaxy clusters “wobble” relative to the cluster’s centre of mass. This unexpected result is inconsistent with predictions made by the current standard model of dark matter. With further analysis it may provide insights into the nature of dark matter, perhaps even indicating that new physics is at work.
Countless galaxies vie for attention in this monster image of the Fornax Galaxy Cluster, some appearing only as pinpricks of light while others dominate the foreground. One of these is the lenticular galaxy NGC 1316. The turbulent past of this much-studied galaxy has left it with a delicate structure of loops, arcs and rings that astronomers have now imaged in greater detail than ever before with the VLT Survey Telescope. This astonishingly deep image also reveals a myriad of dim objects along with faint intracluster light.
In 1926, famed astronomer Edwin Hubble developed his morphological classification scheme for galaxies. This method divided galaxies into three basic groups – Elliptical, Spiral and Lenticular – based on their shapes. Since then, astronomers have devoted considerable time and effort in an attempt to determine how galaxies have evolved over the course of billions of years to become these shapes.