I saw this in the Metro (free London newspaper) and thought it was quite wittily written.
Stage 1: Getting your star to really suck
1. Start with a particularly large star (one about 25 times the mass of our Sun will do).
2. Wait for it to exhaust its supply of hydrogen. This process happens much faster in a large star than in one the size of our Sun - which takes about 9 billion years to run out of fuel - but it will still take about 10 million years (you might want to make a cup of tea here).
3. Don't stand over your star at this point - you'll know when it's used up its hydrogen when it explodes in a supernova.
4. The supernova will throw off the star's remaining gases (put these to one side as you will need them later on), leaving behind a highly compacted, super-dense core.
5. You won't need to interfere here either. The left-over core is so dense - and its gravitational force so powerful - that it continues collapsing until its entire mass is contained within a tiny point called a singularity, or black hole.
6. Don't panic if you don't have a black hole at this point, just try feeding it some of that left-over stellar gas you set aside earlier. This will get pulled into your dense core by gravity and will add to its mass - helping it to collapse further. When it starts dragging in everything that gets too close (including light, which is why they appear black), you have a black hole.
7. At this point, your black hole is still quite small. To make yourself a quasar, you will need to turn your black hole into a supermassive black hole.
Stage 2: Mix
8. To do this, you will need to let your black hole wander around the universe until it comes across another black hole. If they get close enough, their massive gravitational attraction will cause them to begin orbiting each other. As they get closer, this rotational speed will increase until they come together to form a much larger, rapidly rotating black hole. Repeat this process until you have a supermassive black hole.
Stage 3: Light blue touch paper, stand well back
9. Check that your supermassive black hole is rotating quickly enough (this is important if you want to make a quasar). Assuming it is, you will now need to add large amounts of stellar gases (your black hole should have accumulated these as it wandered the universe absorbing other black holes and stripping stars of their gases).
10. These stellar gases will form a rotating cloud surrounding the black hole. As the gas falls into the black hole, it rotates incredibly quickly (like water being sucked down a plug hole). This is where your quasar is 'turned on'. As the gas rotates, friction heats it to millions of degrees causing it to emit massive amounts of thermal radiation (this is what makes a quasar so bright).
11. As the hot gases interact with your black hole's magnetic field, they create magnetic winds and particle jets that spew highly energetic charged particles - gas molecules whose electrons become over-excited by the massive heat - at hundreds of kilometres per second into space.
Congratulations!
You are now the proud owner of a shiny new quasar. Please enjoy responsibly.
Stage 1: Getting your star to really suck
1. Start with a particularly large star (one about 25 times the mass of our Sun will do).
2. Wait for it to exhaust its supply of hydrogen. This process happens much faster in a large star than in one the size of our Sun - which takes about 9 billion years to run out of fuel - but it will still take about 10 million years (you might want to make a cup of tea here).
3. Don't stand over your star at this point - you'll know when it's used up its hydrogen when it explodes in a supernova.
4. The supernova will throw off the star's remaining gases (put these to one side as you will need them later on), leaving behind a highly compacted, super-dense core.
5. You won't need to interfere here either. The left-over core is so dense - and its gravitational force so powerful - that it continues collapsing until its entire mass is contained within a tiny point called a singularity, or black hole.
6. Don't panic if you don't have a black hole at this point, just try feeding it some of that left-over stellar gas you set aside earlier. This will get pulled into your dense core by gravity and will add to its mass - helping it to collapse further. When it starts dragging in everything that gets too close (including light, which is why they appear black), you have a black hole.
7. At this point, your black hole is still quite small. To make yourself a quasar, you will need to turn your black hole into a supermassive black hole.
Stage 2: Mix
8. To do this, you will need to let your black hole wander around the universe until it comes across another black hole. If they get close enough, their massive gravitational attraction will cause them to begin orbiting each other. As they get closer, this rotational speed will increase until they come together to form a much larger, rapidly rotating black hole. Repeat this process until you have a supermassive black hole.
Stage 3: Light blue touch paper, stand well back
9. Check that your supermassive black hole is rotating quickly enough (this is important if you want to make a quasar). Assuming it is, you will now need to add large amounts of stellar gases (your black hole should have accumulated these as it wandered the universe absorbing other black holes and stripping stars of their gases).
10. These stellar gases will form a rotating cloud surrounding the black hole. As the gas falls into the black hole, it rotates incredibly quickly (like water being sucked down a plug hole). This is where your quasar is 'turned on'. As the gas rotates, friction heats it to millions of degrees causing it to emit massive amounts of thermal radiation (this is what makes a quasar so bright).
11. As the hot gases interact with your black hole's magnetic field, they create magnetic winds and particle jets that spew highly energetic charged particles - gas molecules whose electrons become over-excited by the massive heat - at hundreds of kilometres per second into space.
Congratulations!
You are now the proud owner of a shiny new quasar. Please enjoy responsibly.