- #1
CCWilson
- 63
- 0
Say a three solar mass black hole. Would someone notice it before it reached the Kuiper Belt, or only after there were deflections of known bodies in the Kuiper Belt?
CCWilson said:Wouldn't a black hole heading directly toward us maintain almost the same position relative to the stars near its path, from our vantage point? If so, wouldn't the apparent position changes caused by gravitational lensing be subtle? Or would the rotation of the Milky Way cause the black hole to appear (if we could see it) to move in relation to the stars?
I calculated that a while ago, and 100 light years is very close to my result (multiplied by 3 to account for the higher mass here). It is not "pretty obvious", however, unless you have a really good lensing event and not just a change in the position of a star.Chronos said:The gravitational lensing would become pretty obvious by the time it got within about 100 light years.
The same as the rotation of the black hole itself.snorkack said:An accretion disc needs to be rotating. If a black hole is moving through uniform gas, what would be the direction of accretion disc rotation?
The actual black disk has a negligible diameter - impossible to resolve with current technology unless it is in the solar system itself.aerrowknows said:easiest, safest and fastest method would be to watch for anomalies in background galactic radiation. As you know , the galaxy emits a left over gamma or other wavelength radiation from deep space. If a black were to approach us to any reasonable distance , it will block that part out and create a "black spot" on radiation graphs.
CCWilson said:The scenario I'm asking about is where a black hole is going to be approaching us within the next few years. So it's not going to be passing by or through any galaxies other than our own. Is it inevitable that a black hole headed directly toward us would be close enough in line with a star or stars in our galaxy for gravitational lensing to be picked up by observers?
mfb said:I calculated that a while ago, and 100 light years is very close to my result (multiplied by 3 to account for the higher mass here). It is not "pretty obvious", however, unless you have a really good lensing event and not just a change in the position of a star.
In any way, it would be obvious before it comes closer than Alpha Centauri and we would have thousands of years to prepare.
It will exist in the near future with a high probability.Your Gaia is a fictional device. It has never existed.
You don't have to follow the parallax itself, it is sufficient to follow the stellar positions.But if the hole is centuries away then increasing the parallax merely means the stars seem to be nearer than they are. No one would know they are actually not as close unless they follow the parallax over time.
You get 1,75´´ deflection at distance of 5 solar radii, or 3,5 million km.mfb said:If the black hole has more mass (like ~5 solar masses), you get the same deflection with ~1000 AU distance or ~50 years.
mfb said:As the black hole moves so quickly, deflection would change during the observation time. Not 0<->100%, but at least so much that it cannot be closer than ~10 years away.
A black hole is an extremely dense region in space where the gravitational pull is so strong that nothing, including light, can escape from it. Black holes are formed when a massive star dies and its core collapses under its own gravity.
We can detect a black hole using various methods such as observing its effects on the surrounding matter, detecting X-rays emitted from the hot gas falling into the black hole, or observing its gravitational lensing effect on the light from distant stars.
If a black hole was headed directly towards Earth, it would cause catastrophic effects. The immense gravitational pull of the black hole would tear apart everything in its path, including our planet.
The distance at which we can detect a black hole headed towards us depends on its size and the method of detection. With current technology, we can detect black holes up to tens of thousands of light-years away.
No, we cannot accurately predict when a black hole will come towards Earth. Black holes are constantly moving and their paths can be altered by various factors, making it difficult to predict their movements. Additionally, the vastness of space makes it challenging to detect and track all black holes in our vicinity.