![]() They form after the centre of a large star collapses, causing a supernova (the explosion of a star). Stellar-mass black holes are the smallest between 1 and 100 times the mass of the Sun. Astronomers believe that most spiral and elliptical galaxies have black holes at their centres. 1īlack holes are objects with extreme density, and the amount of mass they have means they have so much gravitational pull that even light gets trapped. If the core's mass is more than about three times the mass of the Sun, the force of gravity overwhelms all the other forces, the remnant collapses and produces a black hole. Many questions remain unanswered, but scientists continue to study black holes to unlock these mysteries.Black holes are forged from the small, dense, remnant cores of dead stars. ![]() But this is still a controversial theory, and more research needs to be done.īlack holes are fascinating objects that challenge our understanding of the universe. ![]() And one explanation proposed in February 2023 is that perhaps black holes grow with the expansion of the Universe which could be the case if dark energy was contained in their cores. However, when scientists studied black holes in young galaxies with lots of stars forming which the black holes could feed on, compared to black holes in giant but dormant galaxies that have very little to devour, they found that the black holes in the large dormant galaxies were more massive than they should be – the growth of those black holes must be through a different process. By attracting matter or merging with another black hole. This means that dark energy is essentially an unknown force working against gravity.Įarlier I mentioned that supermassive black holes grow in two ways. Scientists also believe that dark energy is accelerating the expansion of the universe. But what we do know is that it makes up around 70% of the universe. To put this into perspective, this would be changing the distance to the nearest star outside of the solar system (40 trillion km away) by one hair’s width.Ĭould supermassive black holes be the source of dark energy?įirst of all we need to answer the question: what is dark energy? We don’t know much. This discovery was an incredible accomplishment, as the ripple changed the length of a 4 km LIGO arm by a thousandth of the width of a proton. But when a gravitational wave passes through the area, ripples in space-time cause the arms to stretch and compress – so the laser light returning from each arm comes back out of sync. Laser beams are then passed through them and reflected back to a detector – normally the two lasers from the identical beams arrives back in sync. LIGO consists of two identical detectors which have two perpendicular arms 4 km in length with mirrors at the end. In September 2015, the Laser Interferometer Gravitational-Wave Observatory (LIGO) detected the first direct evidence of gravitational waves, caused by the merging of two black holes around 30 times the mass of the Sun. Gravitational waves are ripples in space-time, but these waves are invisible and travel at the speed of light. This would cause ripples to spread out in the water. Einstein believed that when two bodies orbit each other, it causes ripples in space. If two black holes come close to each other they begin to orbit around each other faster and faster. That’s very dense - you’d need pretty strong arms to lift that! A teaspoon of material from a neutron star would weigh as much as Mount Everest. Imagine all the material contained within our Sun being squashed into the distance between Leicester and Loughborough. A neutron star’s mass is around one to two times the mass of the Sun but is only around 20 km in diameter. When massive stars run out of fuel, the star’s core collapses under its own gravity so forcefully, that the outer layers are expelled outwards in a violent supernova explosion. Instead, the Sun will become a white dwarf – a small, dense remnant of a star that glows from its leftover heat after the Sun runs out of fuel. The Sun is a small to medium-sized star and would need to be about 20 times more massive to become a black hole. However, not all stars end up as black holes, only the most massive stars do. Stellar black holes are formed at the end of a star’s lifetime. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |