When was the first time you noticed you where in the 21st century? For some of you it may have been when you owned your first smartphone, or your first electric car, or your fancy 3D TV or 3D printer, or maybe when you tried the google glass? Those are cool little things that may impress you for a while but hardly they’ll make it into the history books. Now really, when was the first time you had a sense that things had already changed? For me that day was this week when I saw this picture. It does not just tell a story, it shows the change that will dominate the 21st century. The Indian Space Research Organisation succesfully put in orbit a small satellite around Mars. The picture shows a group of female scientist/engineers celebrating this tremendous achievement. This picture illustrates the game-changing rules of the 21st century. First, the definite raise of Asia as a superpower in the world. Space missions are normally used by governments as powerful messages to the world. Very few things have the power to bring the attention of the world (in a good way) as a successful space mission. One of the reassons why governments choose space missions to demonstrate their power (economic, technological, militar and even political) is that you can not cheat in space. You either have the will and technology to be succesfull or you don’t. India, together with its Asian neaighbours, is destined to play a leading and fundamental role in the 21st century. But even more imporant, is the second conclusion that we can get form the picture above. What comes to your mind when you think of a rocket scientist? Well, think again. Women also, are destined to play a fundamental and leading role in the 21st century. The 20th century was full of promisses for women, some of them only partially fulfilled. Now reality is here. If one thing will define the 21st century it won’t be the defnite raise of Asia, but the definite raise of women.
MOND and Dragon Kick galaxies.
MOND (MOdified Newtonian Dynamics) models are popular among some scientist because they avoid one of the biggest problems in cosmology, dark matter. This misterious substance remains undetected although there is evidence from several observations that it must exist and in vast quantities. MOND models are able to explain some of these observations by modifying the laws of gravity. In particular, at cosmic distances MOND models propose that the gravitational acceleration does not decay as the inverse of the distance squared but at a smaller rate. This slower decay of the gravitational acceleration would effectively describe some of the observations without the need to invoke the existence of dark matter but it also has its own problems, like fine tunning of the parameters in the models. Together with some collaborators, we recently studied a particular galaxy behind the cluster MACS0416 that is gravitationally lensed (or bended) by another galaxy in the same cluster. We named this galaxy the Dragon Kick galaxy because it rejects the MOND hypothesis and confirms the pressence of a halo of dark matter around the lens galaxy. The Dragon Kick galaxy is shown above as a blue arc that is super-impossed on the legs of our would be Bruce Lee. Our results will be made public next week but basically we find that the lens galaxy (shown above as a yellowish edge-on galaxy emerging from the private region of our Bruce Lee) requires a halo around it that aligns perpendicularly with the lens galaxy in order to explain the shape of the lensed blue arc (the Dragon Kick galaxy) . The mass of this invisible halo (the dark matter) is larger than the mass of the lens galaxy and in agreement with what is expected from the standard model that assumes the existence of vast amounts of dark matter in the universe. More Dragon Kick galaxies are expected to be studied soon that could help in providing new clues about the nature of dark matter.
You can see the original paper here: http://arxiv.org/abs/1409.1578
cosmicspectator 