Ask an Astronomer

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Ask an Astronomer Question: "What is the nearest galaxy to the Milky Way?" segment number: 2007-001 Michelle Thaller: It seems it should be easy to answer the question "What the nearest galaxy to the Milky Way?" But in reality, it’s a little complicated. One way to answer to the question is that the nearest galaxy to us is the Andromeda Galaxy. The Andromeda Galaxy is a large spiral galaxy much like the Milky Way. It's located about 2 million light-years away from us. If you look in the constellation Andromeda, you can actually see this little, fuzzy blob. That, in fact, is the galaxy, and it’s the farthest object you can see with your naked eye. The Andromeda Galaxy is the closest, completely separate, large galaxy to the Milky Way. But, you know, there are other ways to answer this question. The Milky Way actually has two small, blobby galaxies that orbit around it, sort of like moons around a planet. These dwarf galaxies are called the Magellanic Clouds, and they're very easy to see if you happen to be in the Southern Hemisphere. The Large Magellanic Cloud is about 160,000 light-years away. The similar, but slightly smaller Small Magellanic Cloud is about 210,000 light-years away. But it actually gets even more complicated than that! In 1994, astronomers discovered that a dwarf galaxy is actually colliding with the Milky Way right now! This little galaxy is currently about 88,000 light-years away from us in the Constellation Sagittarius. Then, in 2003, astronomers found another dwarf galaxy in the constellation Canis Major. The Milky Way has almost completely eaten this little galaxy up, but the center of this disrupted, smeared out galaxy is only about 25,000 light-years away from Earth. There's no danger to Earth from any of these collisions, but it's interesting to note that we're actually slightly closer to the center of the Canis Majoris Dwarf Galaxy than we are to the center of our own Milky Way! For "Ask an Astronomer," I'm Dr. Michelle Thaller at the Spitzer Science Center. .

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Metallicity Relation in the Magellanic Clouds Clusters,,
A&A 554, A16 (2013) Astronomy DOI: 10.1051/0004-6361/201220926 & c ESO 2013 Astrophysics Age – metallicity relation in the Magellanic Clouds clusters,, E. Livanou1, A. Dapergolas2,M.Kontizas1,B.Nordström3, E. Kontizas2,J.Andersen3,5, B. Dirsch4, and A. Karampelas1 1 Section of Astrophysics Astronomy & Mechanics, Department of Physics, University of Athens, 15783 Athens, Greece e-mail: [email protected] 2 Institute of Astronomy and Astrophysics, National Observatory of Athens, PO Box 20048, 11810 Athens, Greece 3 Niels Bohr Institute Copenhagen University, Astronomical Observatory, Juliane Maries Vej 30, 2100 Copenhagen, Denmark 4 Facultad de Ciencias Astronomicas y Geoﬁsicas, Universidad Nacional de La Plata, B1900 FWA La Plata Buenos Aires, Argentina 5 Nordic Optical Telescope, Apartado 474, 38700 Santa Cruz de La Palma, Spain Received 14 December 2012 / Accepted 2 March 2013 ABSTRACT Aims. We study small open star clusters, using Strömgren photometry to investigate a possible dependence between age and metallicity in the Magellanic Clouds (MCs). Our goals are to trace evidence of an age metallicity relation (AMR) and correlate it with the mutual interactions of the two MCs and to correlate the AMR with the spatial distribution of the clusters. In the Large Magellanic Cloud (LMC), the majority of the selected clusters are young (up to 1 Gyr), and we search for an AMR at this epoch, which has not been much studied. Methods. We report results for 15 LMC and 8 Small Magellanic Cloud (SMC) clusters, scattered all over the area of these galaxies, to cover a wide spatial distribution and metallicity range. The selected LMC clusters were observed with the 1.54 m Danish Telescope in Chile, using the Danish Faint Object Spectrograph and Camera (DFOSC) with a single 2k × 2k CCD.
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© 2016 Kalmbach Publishing Co. This material may not be reproduced in any form without permission from the publisher. www.Astronomy.com OUR SOLAR SYSTEM Realms of fire and ice We start your tour of the cosmos with gas and ice giants, a lot of rocks, and the only known abode for life. by Francis Reddy cosmic perspective is always a correctly describe our planetary system The cosmic distance scale little unnerving. For example, we as consisting of Jupiter plus debris. It’s hard to imagine just how big occupy the third large rock from The star that brightens our days, the our universe is. To give a sense of its a middle-aged dwarf star we Sun, is the solar system’s source of heat vast scale, we’ve devoted the bot- call the Sun, which resides in a and light as well as its central mass, a tom of this and the next four stories Aquiet backwater of a barred spiral galaxy gravitational anchor holding everything to a linear scale of the cosmos. The known as the Milky Way, itself one of bil- together as we travel around the galaxy. distance to each object represents the amount of space its light has lions of galaxies. Yet at the same time, we Its warmth naturally divides the planetary traversed to reach Earth. Because can take heart in knowing that our little system into two zones of disparate size: the universe is expanding, a distant tract of the universe remains exceptional one hot, bright, and compact, and the body will have moved farther away as the only place where we know life other cold, dark, and sprawling.
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