100,000 Stars. The Millenium Simulation HD - A journey through the Universe. Top 100 Images. Maapallolle on osunut valtava gammasädepurkaus - Mistä se tuli? Avaruustutkijat huomasivat viime vuonna, että maapallo on joutunut hyvin voimakkaan gammasädepurkauksen kohteeksi.
Nyt tutkijat ovat ajoittaneet purkauksen ja myös selvittäneet, mistä se oli peräisin. Gammasädepurkaus tuli ilmi, kun tutkijat havaitsivat outoja säteilyjäämiä vanhoissa seetripuissa ja Etelämantereen jäässä. Kyseisiä isotooppeja syntyy vain, kun atomit joutuvat erittäin voimakkaan säteilyn kohteiksi yläilmakehässä. Puiden vuosirenkaita tutkimalla säteilypurkaus ajoitettiin joko vuodelle 774 tai 775, jolloin Euroopassa elettiin keskiaikaa. Gamma-ray burst 'hit Earth in 8th Century' 21 January 2013Last updated at 01:00 ET By Rebecca Morelle Science reporter, BBC World Service Gamma-ray bursts can occur when two neutron stars merge A gamma ray burst, the most powerful explosion known in the Universe, may have hit the Earth in the 8th Century.
In 2012 researchers found evidence that our planet had been struck by a blast of radiation during the Middle Ages, but there was debate over what kind of cosmic event could have caused this. Now a study suggests it was the result of two black holes or neutron stars merging in our galaxy. Tähtitieteilijät löysivät "maailmankaikkeuden suurimman asian" Brittiläiset tähtitieteilijät ovat löytäneet kaukaa avaruudesta kvasaariryhmän, jota pidetään maailmankaikkeuden ylivoimaisesti suurimpana materiakeskittymänä.
Valon nopeudella etenevältä avaruusalukselta kestäisi matka kvasaariryhmän laidalta toiselle jopa neljä miljardia vuotta. Kvasaarit ovat hyvin kaukaisia kohteita, jotka sykkivät voimakasta valoa. Tutkijoiden mukaan ne voivat olla galaksien esiasteita, jotka tietyssä kehitysvaiheessa lähettävät avaruuden kirkkainta valoa. Kvasaareilla on taipumus muodostaa ryhmiä. Löydön tehneet brittiläisen Central Lancashiren yliopiston tutkijat ovat ihmeissään, sillä valtava löytö uhmaa Albert Einsteinin kosmologista periaatetta, jonka mukaan maailmankaikkeus on symmetrinen kokonaisuus eli se näyttää samanlaiselta riippumatta siitä, mistä kohtaa sitä tarkkailee. Astronomers discover the largest structure in the universe. An international team of astronomers, led by academics from the University of Central Lancashire (UCLan), has found the largest known structure in the universe.
The large quasar group (LQG) is so large that it would take a vehicle travelling at the speed of light some 4 billion years to cross it. The team publish their results in the journal Monthly Notices of the Royal Astronomical Society. The coloured background indicates the peaks and troughs in the occurrence of quasars at the distance of the LQG.
Darker colours indicate more quasars, lighter colours indicate fewer quasars. The LQG is clearly seen as a long chain of peaks indicated by black circles. Since 1982 it has been known that quasars tend to group together in clumps or 'structures' of surprisingly large sizes, forming large quasar groups or LQGs. Biggest black holes may be ten times more massive than we thought. Most large galaxies host a supermassive black hole, ranging from millions to billions of times the mass of the Sun.
Based on the study of many systems, astronomers discovered a correlation between certain properties of a galaxy and the mass of its central black hole. This relationship seems universal, but we've only been able to examine a subset of the galaxies out there. Black hole masses have only been measured for some of the biggest galaxies in the local Universe—the bright, massive galaxies that sit at the centers of galaxy clusters. A recent study has used an independent means of estimating black hole masses, based on their brightness in X-rays and radio light.
J. Blazing Black Holes Spotted in Spiral Beauty. This new view of spiral galaxy IC 342, also known as Caldwell 5, includes data from NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR.
High-energy X-ray data from NuSTAR have been translated to the color magenta, and superimposed on a visible-light view highlighting the galaxy and its star-studded arms. NuSTAR is the first orbiting telescope to take focused pictures of the cosmos in high-energy X-ray light; previous observations of this same galaxy taken at similar wavelengths blurred the entire object into one pixel. The two magenta spots are blazing black holes first detected at lower-energy X-ray wavelengths by NASA's Chandra X-ray Observatory. Nasa löysi galaksista vauvaikäisen mustan aukon.
Mini Black Holes Easier To Make Than Thought. Creating microscopic black holes using particle accelerators requires less energy than previously thought, researchers say.
If physicists do succeed in creating black holes with such energies on Earth, the achievement could prove the existence of extra dimensions in the universe, physicists noted. Any such black holes would pose no risk to Earth, however, scientists added. Black holes possess gravitational fields so powerful that nothing can escape, not even light. The holes normally form when the remains of a dead star collapse under their own gravity, squeezing their mass together. A number of theories about the universe suggest the existence of extra dimensions of reality, each folded up into sizes ranging from as tiny as a proton to as big as a fraction of a millimeter.
When the most powerful particle accelerator in the world, the Large Hadron Collider, was coming online, scientists wondered if it might become a "black hole factory," generating a black hole as often as every second. Exoplanet Catalog Reveals 7 Possibly Habitable Worlds. A new catalog aims to list all the known planets in the galaxy that could potentially be habitable to life.
The count is at seven so far, with many more to come, researchers said. The online listing, called the Habitable Exoplanets Catalog, celebrated its first anniversary today (Dec. 5). When it was first released last year, it had two potential habitable planets to its name. Astronomers Say 1 in 6 Stars Has an Earth-Sized Planet. Astronomers analyzing Kepler data have determined that about 17% of stars have an Earth-sized planet in an orbit closer than Mercury.
Since the Milky Way is estimated to have about 100 billion stars, this means there are at least 17 billion Earth-sized worlds in our galaxy.