I'm definitely pro vaxxer. My son's first vaccination might have initiated an autoimmune disease not previously registered in Danish children, but he is getting all of the vaccines anyways.
Now, that hydrocarbon have flowing from American soil again, American depend even less from Venezuela.
One of the big questions many people have about black holes is what happens when something enters one. A recent Cosmos episode not withstanding, there is no reason to suspect that entering a black hole would take you to an alternate universe. If you were to fall into a black hole, you would simply be in the black hole. What happens to you after that depends upon the nature of quantum gravity, which we still don’t fully understand.
Of course all of this is according to general relativity. While general relativity has been confirmed by multiple experiments, what evidence do we have of things falling into a black hole? It turns out we have lots of broad evidence, and a bit of specific evidence. The broad evidence comes from the observation of active galactic nuclei (AGN), which includes things like quasars, blazars and radio galaxies. These highly energetic objects are powered by active black holes. Comparison of these objects to black hole models show strong agreement. We know, for example, that black holes can develop an accretion disk of matter being consumed, as well as large jets of particles streaming from their poles.
We also have some evidence of black holes consuming individual stars. In 2011, the Pan-STARRS telescope observed what initially appeared to be a supernova at the center of a galaxy about 2.7 billion light years away. The spectrum of this burst indicated a large presence of helium, but no evidence of hydrogen. This means it was not likely just some gas captured by the black hole (which would be a mix of helium and hydrogen), but rather due to the core of an old star (which is mostly helium) being captured.
Closer to home, we can observe a cloud of gas near the supermassive black hole in our own galaxy as it is gradually being torn apart. In this case the cloud isn’t directly being consumed by the black hole, but the way in which the cloud is being torn apart has matched computer simulations of such close encounters.
So we actually have a good understanding of what happens to things as they fall into a black hole. There are still questions yet to be answered, but our black hole models are rooted in observational evidence.
Image: Simulation of a star near a black hole. NASA/JPL-Caltech/JHU/UCSC
Astronomers have found an asteroid with a ring system, and the results have been published Nature (pdf: http://goo.gl/kvPF2u). While this is the first discovery of a ring system about an asteroid, such a thing isn’t entirely unexpected. We have known for a while that asteroids can have moons, for example. But what’s particularly interesting is how they discovered these rings.
The asteroid in question is known as Chariklo, a 130 kilometer wide object that orbits between the orbits of Saturn and Uranus. It is the largest example of the Centaur group, which are likely Kuiper belt objects that were captured by the gravitational pull of the outer planets. In the Summer of 2013, Chariklo passed in front of a dim, 12th-magnitude star as seen from parts of South America. It is a phenomenon known as an occultation.
Such an event is a great opportunity to better determine the size and shape of an asteroid, so a team of astronomers dispersed through Brazil, Argentina, Uruguay and Chile made observations of the occultation. Since each observation is made from a different vantage point, Chariklo’s occultation of the background star occurs at a slightly different orientation. By combining these different observations the team could map the overall shape of the asteroid.
But what the team found was that from some vantage points the background star dimmed a couple times before being occulted by Chariklo, then dimmed a couple times after the occultation as well. Analysis of these pre and post dips makes it pretty clear that there are at least two rings around the asteroid.
Knowing that Chariklo has a ring system, the team was also able to determine a bit about the composition of the rings. As Chariklo (or any other ringed object) orbits the Sun, there are times when the rings are seen more edge on, and times when we see more of the rings. The team compared spectral observations of the asteroid between 1997 and 2008, and found that the asteroid gradually dimmed during that period. The observation of water ice in the spectrum also faded during that period. This would be consistent with a ring system containing ice (which is very reflective) gradually shifting to an edge-on orientation.
One of the more surprising aspects of the discovery is that the rings are so sharp and dense. Typically a ring system would diffuse over time unless there are shepherd moons to keep the rings in order. So it may be that Chariklo has not only a ring system, but a moon system as well.
To determine whether that is the case, it will likely take some high resolution imaging. But that remains to be seen.
Image: Lucie Maquet
Paper: F. Braga-Ribas, B. Sicardy, et al. A ring system detected around the Centaur (10199) Chariklo. Nature (2014) doi:10.1038/nature13155.
- Steno MuseetPlanetarieassistent og Foreviser, 2006 - present
- FreelancePublic Lecturer, 2000 - present
- Varde Gymnasium og HF-KursusPhysics Teacher, 2011 - 2012
- Østerbyens Dyrlæger2005 - 2005
Sometimes i work at the Steno Musemum in the planetarium.
In my spare time i do politics, play guitar, read and watch movies and foremost play roleplaying games, pen and pape and lots of Live Action.
- University of AarhusMaster - Astrophysics, 2009 - present
- University of AarhusBachelor - Physics and Astronomy, 2005 - 2009
- Varde Gymnasium og HF-kursusHigh-School: Science, 2002 - 2005
- Næsbjerg SkoleBasic School, 1999 - 2002
- Nordenskov SkoleBasic School, 1996 - 1999
- Scuola Elementare RipalimosaniBasic School, 1993 - 1996
- Scuola Elementare "Giovanni Paolo II", CampobassoBasic School, 1992 - 1993
- Primina in "Regina Mundi", CampobassoBasic School, 1991 - 1992
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