Nasa’s Roman Mission Will Hunt for Primordial Black Holes

https://www.nasa.gov/missions/roman-space-telescope/how-nasas-roman-mission-will-hunt-for-primordial-black-holes/

by gmays • 2 years ago

140 76 2 years ago

api2• 2 years ago

Primordial black holes are a fascinating topic. One of my favorite hypotheses is that "planet nine," a large possibly 1-5 Earth mass planet suggested by some orbital models to exist beyond Neptune and Pluto in the far outer solar system, may be a primordial black hole.

If such a thing existed it'd be a black hole about the size of a billiard ball and would be extremely hard to detect. It would not emit Hawking radiation (Hawking temperature still below the CMB), so the only thing it would emit would be when it encountered something and tore it apart. In that case you'd see X-rays, gamma rays, etc., but maybe only briefly. Only way to find it might be to model orbits accurately enough to predict its position and then look for gravitational lensing.

If this companion object did exist it'd be a gigantic discovery of huge importance. It'd be within reach of probes, making it possible to study and even do experiments on to investigate things like quantum gravity. It could also be used in tight gravity assist flybys to accelerate probes to incredible velocities, maybe making interstellar probes a lot more practical. It'd be our very own way to yeet stuff to the stars, assuming these things could withstand insane g-forces (so probably not humans unfortunately).

ryandrake• 2 years ago

It could also be used in tight gravity assist flybys to accelerate probes to incredible velocities, maybe making interstellar probes a lot more practical.

Would 1-5 earth masses really provide enough of a yeet to appreciably affect the speed of a probe? Jupiter is about 300+ earth masses and we're not flinging probes out to stars using him.

dooglius• 2 years ago

We did, Voyager 1 and 2 used Jupiter to get out of the solar system

bigyikes• 2 years ago

You can get a lot closer to the center of mass of the black hole, which should drastically increase acceleration since it falls off with distance squared.

caf• 2 years ago

Assuming you don't go so close that tidal effects tear the probe apart, the g-forces should only be those imposed by the probe's thrusters firing during the assist. When the thrusters aren't firing it's just in free-fall.

kadoban• 2 years ago

Hm, that can't be how that works, can it? How do you get any extra velocity then if there's never any acceleration beyond what your thrusters provide?

Loughla• 2 years ago

I feel like if you were close enough for a gravity assist, wouldn't the tidal forces just tear the probe apart?

Tostino• 2 years ago

Not necessarily. If you replaced the sun with an equivalent mass black hole, none of the orbits of the planets would change.

sandworm1013• 2 years ago

The tidal forces would be no different than using jupiter for an assist. You would still have the probe pass by at several thousand, several tens of thousands of kilometers. A close-in gravity assist may look better on paper, but the practicalities and speeds of such a thing are risky. One small error and the mission would be over quick, launched out at a radically incorrect trajectory.

sandworm1013• 2 years ago

At that size, very few things would ever get close enough to be torn apart, let alone fall in. We should look for objects suddenly changing course ivo the potential black hole.

perihelions3• 2 years ago

- "In that case you'd see X-rays, gamma rays, etc., but maybe only briefly."

One speculative possibility is that we could find a continuous gamma annihilation signal from its dark matter halo,

https://arxiv.org/abs/1909.11090

https://hn.algolia.com/?query=What%20If%20Planet%209%20Is%20...

breckenedge• 2 years ago

I really want primordial black holes to turn out to be the missing antimatter from the Big Bang, but I don’t think that could ever be tested. And of course a mechanism for this would probably need new physics since antimatter interacts the same as normal matter wrt gravity.

stainablesteel• 2 years ago

it sounds a lot like it now that i read this, large dispersed amounts of antimatter that apparently doesn't give off light yet has massive gravitational pull

nullserver• 2 years ago

https://youtu.be/qy8MdewY_TY?si=NVZzWJSFXl4EATRK

Good video on topic

ccgreg• 2 years ago

Antimatter has the same electrodynamic properties as matter.

pfdietz2• 2 years ago

There were suggestions that the antimatter-matter asymmetry is because antimatter was preferentially segregated into a dense phase of hadronic matter, like quark matter nuggets. This would be interesting because if such nuggets could be found and captured, they'd be a potential source of energy by annihilation with ordinary matter.

exe342• 2 years ago

Spicy nuggets.

NegativeLatency• 2 years ago

preferentially segregated into a dense phase of hadronic matter

Sounds interesting, where can I read more theories about this?

dreamcompiler• 2 years ago

What happens when an antimatter black hole collides with a matter black hole? We'd see gravitational waves but no photons, right? Would the grav waves reflect the tremendous energy release somehow?

at_a_remove4• 2 years ago

No.

The "no hair theorem" states that black holes preserve exactly three numbers: mass, charge, and angular momentum. Baryon number, lepton number (as you would see in antimatter) are not conserved, the information is lost.

And, no, antimatter does not have negative mass, in any of the three contexts (mass-energy equivalence, inertia, and gravitational).

Therefore, a black hole fed entirely by antimatter would be indistinguishable from a black hole fed entirely by the equivalent matter.

azernik• 2 years ago

An alternate explanation to the no-hair one:

In a black hole, all you see from the outside is total mass. This is actually mass-energy - a release of energy inside the black hole doesn't change the total mass-energy inside.

deepsun4• 2 years ago

When I asked similar questions physicists, turns out all of them were thought off and tested long time ago. E.g. small black holes would still cause detectable and attributable radiation.

woopsn• 2 years ago

Fascinating mission. I don't understand how microlensing events resulting from primordial black holes can be differentiated even statistically, given that they "can't be formed by any known physical process", but in any case it's exciting to discover there's much more of something up there than we knew. Even if they are "just" rogue planets.

api2• 2 years ago

We have a variety of ways to make insanely precise measurements of light to the point of counting photons. I’m guessing that factors into being able to detect microlensing.

hyperific• 2 years ago

NASA in the title should be all capital letters as it's an acronym and not a name.

jdminhbg• 2 years ago

Depends on where you live: https://proofreadingpal.com/proofreading-pulse/writing-guide....

ibeforee3• 2 years ago

nasa.gov is the domain here

ralferoo• 2 years ago

As a Brit, I've never noticed NASA spelt Nasa before, and I'm on the fence about Unesco, not because I recall seeing it title-caps, but because it doesn't look offensive to me.

That said, when I googled for the title-caps variants of both words, I saw the Guardian, Independent and Times all used it for Nasa, but only the Guardian and Times seem to use it for Unesco. There was also a page from the NYT that used Unesco, so a counter example from the US, but even the UK government pages refer to it in all caps, as do most other UK articles.

I certainly find it a weird generalisation that "UK English" (sic) prefers title-caps, as we tend to like our abbreviated names and pretty much always use all-caps when every letter comes from a separate word, and only title-caps when we use runs of letters from each different word - quango (quasi-NGO), Bakerloo (Baker St-Waterloo), Beeb (compared with BBC), Lib Dems, etc. We also have a few things that aren't consistent for government things - Defra (always used to be DEFRA, but they seem to have rebranded), MOD (always caps), Ofqual (=Office of Qualifications, always title case), Ofcom (=Office of Communications, now seems to officially be title case, but always used to be OFCOM), UCAS (University and Colleges Admission Scheme, always all-caps), etc.

Maybe the stylistic choice is based on how pronounceable it is as a word, but whatever I don't think there are any hard and fast rules!

consumer451• 2 years ago

HN automatically makes various changes to submission titles. The lesson that should be learned is that after submitting, there is a short period of time where the user can edit the title back to what it should be, in cases such as this.

kristianp• 2 years ago

Launching by May 2027. Was hoping it would be sooner, given the presence of this article, but it seems they drip feed them out gradually.

https://science.nasa.gov/mission/roman-space-telescope/

chefkd• 2 years ago

question for the initiated: why do space agencies divide their resources and attention between different projects? Wouldn't it make sense to focus first on making the moon and it's resources accessible kind of like airplanes then systematically expand to Mars, asteroid belt, and so on instead of spreading out too thin without conquering the closest

macintux• 2 years ago

Purely speculative:

- Betting everything on a single huge project is risky. You wait for years for completion, and if some critical part of the project costs more/takes longer than expected (much like Artemis today) you risk achieving nothing at all.

- Small, cheap projects that don't bankrupt the agency if they fail, when they succeed, generate ongoing positive PR and scientific results. NASA famously promoted this concept after one or two expensive projects had problems (of course, not famously enough that I remember more details).

- Some of those smaller projects are critical, like climate monitoring. You can't just set aside those sorts of tasks for a literal moonshot.

- Smaller projects contribute towards the big ones: NASA has given SpaceX a fair bit of money over the years that is paying off with Starship and Artemis.

mrcwinn• 2 years ago

What the heck is "Nasa"? Not the sword I'll prefer to fall on, but even if you're in the UK, let's honor that this organization is in the United States and they self-describe as "NASA."

scotty793• 2 years ago

I believe that most black holes in the universe are primordial. Even most of the star sized ones. And definitely the supermassive ones.

But it would be super nice to find the ones with masses that are unexplainable in the current framework.

luyu_wu• 2 years ago

Why would you believe this? Stars collapse into black holes all the time as long as they're over the threshold mass.

scotty793• 2 years ago

Mostly because time slows as things approach event horizon.

I know that in the frame of reference of infalling object everything seems like business as usual but for far away observer (us) nothing ever crossed any event horizon.

You can't do away with this problem without dismissing the notion of any well defined simultaneity altogether (which people do, but I believe it's a cop out).

As far as I'm concerned there just wasn't enough time since the beginning of the universe for any blackhole to form, from our point of view, because of the infinite time dilatation. And I think our (remote observer) point of view is what counts because most places in the universe are remote observers.

If you are interested in the rest of my cosmological beliefs I believe that black holes are primary form of matter, the rest is just a dust between them.

I believe that big bang wasn't the beginning of time and space but rather highly energetic event caused by collision of two superdense clusters of trillions of supermassive balckholes. What inflates space is the kinetic energy imparted on the dust by this collision. The mass flies away in all direction with random velocities and the spacetime is "dragged" by it.

We all came from the dust swirling between them that got heated by the event to the energies of quark gluon plasma and higher.

We are also possibly under the influence of very strong, very long wavelength gravity waves originating from outside of observable universe. Larger remaining chunks of the objects that collided to give birth to our universe might be the source.

https://www.researchgate.net/publication/330726290_Confirmat...

Nasa’s Roman Mission Will Hunt for Primordial Black Holes

Related Stories