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Awesome! Thanks for joining us @DrJoePesce. I'll stick to a, possibly, lighter question. As a Star Trek fan... who is your favorite Captain? And what do you think of the new Picard series?
This is the question that's going to get me into the most trouble !
I love all the Captains, because I love the entire Star Trek franchise. BUT it's got to be Kirk for me; followed closely by Picard (I'm loving the new series by the way).
You didn't ask, but to make even more trouble, I will let you know my favorite character (limited to TOS at least). You might have said Spock, since he's a scientist; maybe Kirk, because of leadership. Sulu, because he started out as an astrophysicist (or Physicist in the Astro Science Department - but we know that's an astrophysicist). These are all great suggestions (and great characters). But my favorite is Scotty: He's calm and collected, and is the intellectual equal of Spock. He may not be as quick as Spock (but who is), but he's not far behind and is insightful at the same level. (And he's British, and I'm an anglophile.)
So there!
Ironies add flavor to many facts...
Since a person could go unharmed in passing across the EH (Event Horizon) of a SMBH but become "spaghettified" if it were a smaller one, do you happen to know what the cut-off point (pun intended
In a general sense, you are correct about spaghettification. It really is, on a hand-waving level, the difference between stellar-sized black holes and super massive ones which is your cut-off point.
But just because you might not get spaghettified in a supermassive black hole doesn’t guarantee you being unharmed. Indeed, I think it highly unlikely you would survive a fall into a supermassive black hole. For one thing, the radiation environment is intense: For a “feeding” supermassive black hole, there’s a swirling, billion-degree, plasma in the accretion disk. Lots of very high-energy electromagnetic radiation (think gamma-rays and x-rays), probably a strong magnetic field, and lots of charged particles moving near the speed of light. You wouldn’t last long…. Even a non-feeding supermassive black hole is going to have a hostile (for us) near environment.
My question is about the Centaurus system. Clearly, it's our next port of call after the solar system; I understood that there was a discussion about sending a probe. Do you know if this is a baseless rumour, or might that be on the cards? I believe Proxima has at least one planet.... have you any information?
[I enjoyed your owlish One, Two, Three for the Tootsie Pop!]
But speaking of EM with black holes, I was puzzled when LIGO events, IIRC, (with optical backup) report no EM emissions for BH mergers. Yet, I understand that entropy correlates with the amount of surface (EH) of a black hole, so if two BHs merge, there should be a significant entropy change given the new surface area (i.e. entropy) net result. To get only a gravity wave, and apparently nice and sinusoidal(?), seems counter intuitive, at least for this non-scientist. Could the EM be just too weak for us to detect given the distances, or is the lack of EM predicted in GR?
Yeah, I'll try to remember to pass through a polar region and away from that disk, assuming it's free of bi-polar flows.
But speaking of EM with black holes, I was puzzled when LIGO events, IIRC, (with optical backup) report no EM emissions for BH mergers. Yet, I understand that entropy correlates with the amount of surface (EH) of a black hole, so if two BHs merge, there should be a significant entropy change given the new surface area (i.e. entropy) net result. To get only a gravity wave, and apparently nice and sinusoidal(?), seems counter intuitive, at least for this non-scientist. Could the EM be just too weak for us to detect given the distances, or is the lack of EM predicted in GR?
Hi Joe, been awhile. I’ve been wondering what your thoughts are about some of the recent estimates about the number of possible planets just here in the Milky Way (trillions), and how that might influence estimates of possible life, and other intelligent species. I’m thinking, there must be a very significant number, likely not all carbon based, but still a lot.
I don’t know any more than what has been in the press. It would be interesting to send a probe to the Alpha Centauri system, but that’s probably not yet possible. Of course, it all depends on how long you want to wait for the probe to arrive – it’s easier to send a slower probe than a faster one. In any case, such a mission would be a high-speed flyby of a very small probe (that is, it wouldn’t stop there and orbit any planets – at least not the first probe or two): Snap a couple of images and keep going. Still, it would be quite an accomplishment, and, fascinating.
I live in a high-rise building where I can see (weather permitting!) every sunset as it tracks across the horizon. As my handle implies, I stop whatever I am doing to watch sunsets! Presently I am awaiting the first hint that Sol is heading south again after its six-month journey north! Where may I please find a resource (ideally printed, but also online if needed) that will tell me "Everything I Always Wanted to Know About the Track of the Sun Across the Sky, But Were Afraid to Ask"? My primary questions are (1) degree-difference from sunset to sunset each day (where the disk first touches the horizon), (2) degree-difference from first touch to complete exit of the disk (landmarks tell me there is a difference!), (3) allowing for speed of light I assume the physical sun is already below the horizon when I see it touch the horizon(?), finally (for this, ahem, space) (4) I presume the angle of descent is merely dependent upon the angle of the sun for that day throughout the course of year. And (5) I presume my lat-long have a huge bearing on all this. Now you see why a resource would be helpful! Lots of questions! Thanks! PS (6) Eclipse shades or ________ to safely look directly at the sun for a long period, which I do not do at present! (edited per rules and such)
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Thank you very much for answering my question. And what do you think is the next threshold ?. What is next after a blackhole if eons pass and a blackhole keeps feeding matter ?
Q1. As a teacher, I often hear that people lay blame on teachers for the slip in science-literacy in the USA. What do you feel is the greatest hurdle to science-literacy, and how might the USA improve it?
Q2. Explain why or why not, what do we need to understand, to find out whether it is possible for a probe or human to pass the event horizon, and then return to normal space {provided he or she or could travel there}?
Q3. Elon Musk has been commenting, "We must pass The Great Filter[.]" How do you think our relationship with black holes might change as we become a space-faring species?
Q4. I guess it's not really your forte....though, I am sure you are familiar with the under-funding of science. Why are we so insistent on manned missions to Mars? Wouldn't it make more sense to colonize the Moon (proximity) or Venus? Why no interest in Venus, it's atmosphere is full of resources; given the wind speed is not an issue, I imagine we already have the technology to build a "cloud-city" at the right altitude? Other than the presence of water, Mars seems inferior to colonize - not enough gravity, no magnetosphere, no atmosphere (well a lot less than Earth).
Thank You For Taking Time.
Q2. Explain why or why not, what do we need to understand, to find out whether it is possible for a probe or human to pass the event horizon, and then return to normal space {provided he or she or could travel there}?
Q3. Elon Musk has been commenting, "We must pass The Great Filter[.]" How do you think our relationship with black holes might change as we become a space-faring species?
Q4. I guess it's not really your forte....though, I am sure you are familiar with the under-funding of science. Why are we so insistent on manned missions to Mars? Wouldn't it make more sense to colonize the Moon (proximity) or Venus? Why no interest in Venus, it's atmosphere is full of resources; given the wind speed is not an issue, I imagine we already have the technology to build a "cloud-city" at the right altitude? Other than the presence of water, Mars seems inferior to colonize - not enough gravity, no magnetosphere, no atmosphere (well a lot less than Earth).
Thank You For Taking Time.
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Hi Dr Joe
I have a few questions for you!
Q1: In the far future would the descendants of humans will be able to travel between universes in the multiverse or between dimensions by manipulating the laws of nature? Or we'll be struck in this lone universe until it dies?
Q2: Are you optimistic about the recent possible detection of the axion particle or is it just an error?
Q3: which theory of physics that you think that is the best candidate for a theory of everything?Is it string theory ,loop quantum gravity or something else?
Thank you!
I have a few questions for you!
Q1: In the far future would the descendants of humans will be able to travel between universes in the multiverse or between dimensions by manipulating the laws of nature? Or we'll be struck in this lone universe until it dies?
Q2: Are you optimistic about the recent possible detection of the axion particle or is it just an error?
Q3: which theory of physics that you think that is the best candidate for a theory of everything?Is it string theory ,loop quantum gravity or something else?
Thank you!
Greetings! Well, i have alot of questions but for now i think two will be fine.
1.) It is a known fact that time gets distort near the event horizon of black hole due to the intensive gravitational force, but since time has no physical form so how can gravity or any other force affect it?
2.) As per the news, in the recent years , number of cases of ufo sightings registered has increased to a high rate, so is there any true evidence regarding presence of extraterrestrial life?
Thank you.
1.) It is a known fact that time gets distort near the event horizon of black hole due to the intensive gravitational force, but since time has no physical form so how can gravity or any other force affect it?
2.) As per the news, in the recent years , number of cases of ufo sightings registered has increased to a high rate, so is there any true evidence regarding presence of extraterrestrial life?
Thank you.
[I enjoyed your owlish One, Two, Three for the Tootsie Pop!]
Yeah, I'll try to remember to pass through a polar region and away from that disk, assuming it's free of bi-polar flows.
But speaking of EM with black holes, I was puzzled when LIGO events, IIRC, (with optical backup) report no EM emissions for BH mergers. Yet, I understand that entropy correlates with the amount of surface (EH) of a black hole, so if two BHs merge, there should be a significant entropy change given the new surface area (i.e. entropy) net result. To get only a gravity wave, and apparently nice and sinusoidal(?), seems counter intuitive, at least for this non-scientist. Could the EM be just too weak for us to detect given the distances, or is the lack of EM predicted in GR?
Ah, an excellent question. As far as I know, GR does not rule out EM emission in these mergers. The current thinking is that there IS EM emission, but just below the level of detection with our instruments. Of course, we don’t know that for sure: Are we not detecting it because we can’t see it, or because it’s truly not there.
Bill, it’s good to see you here! Yes, probably lots and lots of planets. Of course, our estimates of life are statistical analyses, based on lots and lots of assumptions. AND, many of those assumptions based on a sample of one (we know of life only on Earth): Science doesn’t really like samples of one! My opinion: LOTS of planets (but how many are truly hospitable to life, but as we know it and in other forms). LOTS of lower life forms (think single-celled life forms, blue-green algae, etc.). Maybe more intelligent life too, but with a much lower probability.
That's fantastic! And I'm glad you are still able to look up even given some constraints!
I’m going to need to do some research for you on this response. There are lots of resources on the web for sun tracking, however, ranging from astronomy to gardening to solar power. You might also want to look up and read the documents describing the “analemma”. You could start here: https://www.space.com/search?searchTerm=analemma
Maybe you could even photograph the analemma from your location! Wouldn't that be cool?
Thank you for your questions!
A1. Good question and a complicated issue. I can’t do it justice in this space, but here are some quick thoughts: 1. In my (limited and anecdotal) experience I have not seen a loss of interest or lack of science literacy in the over 35 years I have been involved explicitly in science (in fact it's been to the contrary - a great deal of interest and growing literacy), 2. we need science now more than ever, 3. Now more than ever, there are lots of high-tech devices that people have to deal with on an everyday basis, and 4. There are lots of sources of information people have to understand and categorize in order to make good decisions. All of these things, I think, make us both more tech savvy, but also more science skeptical. I think understanding how to assess information and make decisions (solve problems) are skills that should be at the forefront of our tool chest. AND having a teacher like you who encourages intellectual exploration is tremendously important.
A2. The answer is simple: Once information has passed through the event horizon of a black hole it cannot come back out. So that means we cannot travel in our spaceship through the event horizon and come back out to tell our tale. Nor could we send a robotic probe in and have it transmit info out to us.
A3. I’m not sure we will gain any further insight into black holes just because we become space faring. I think we will gain more insight as our technology advances. See, for example, the Event Horizon Telescope first-ever image of the region near a black hole. This is a feat of technological advancement: www.nsf.gov/blackholes
A4. All areas of exploration are the right ones! All places you mention would be useful to our understanding of the universe (and fun and interesting!). The priorities, are, of course, cost and technology (which is related to cost).
I know that as a scientist you need to base your experiments on what is already known, but, could we divergently speculate that there could be other forms of what we call “life”, non-carbon based, but based on other elements, that evolved in totally different conditions and has been totally undetectable to human instruments and senses?
Great!
A1. My response would be my opinion – not based on any particular scientific insight. And, first of all, we need to address the point of whether or not there are multiple universes. This is still a topic of science fiction, not science. After that – anything could be possible!
A2. I only know what I’ve seen in the press. The results are not yet strong, and there are three interesting possibilities (maybe more): Experimental contamination, new physics related to the neutrino, or the detection of the axion. If I were pressed to answer your question without any further info, I suspect the result is contamination. The other two possibilities are intriguing and it would be great if they ended up being the answer.
A3. There are lots of pros and cons for each. For me the jury is still out – primarily because none of the candidates have been tested as much as necessary to make a distinction (in my view).
Hello Palak!
A1. Space and time are linked! And so, the gravitational distortion of space distorts time too. This is most noticeable in regions of intense gravity (like near a black hole), but it happens (and is measured) everywhere: If you go on a flight from Washington, D. C. to London, and I stay in Washington, D.C., our clocks will be different (because while flying you are farther from the gravitating mass of the earth than I am). The time signal from GPS satellites must be corrected because they are far above the Earth. If you have a highly accurate clock, you can “easily” measure the difference in time (caused by gravity) if the clock is sitting on the floor versus on a tabletop.
A2. There have been a number of studies (from the 1950s) indicating the rate of ufo sightings increases with economic or social distress. I don’t know if this is the cause of what you mention or not, but it is a known issue. We currently have no evidence of extraterrestrial life, of any sort (neither single-celled amoebas nor intelligent life forms). My view is that there are lots of natural (and psychological) phenomena that explain ufo sightings. Some may remain truly “unidentified”, but I don’t believe they are extraterrestrial visitors.
Hey - thanks for the question!
What is known certainly serves as a foundation and basis for experiments. But in astronomy I’ve found (including often in my own experience) that most of what we know today was completely unexpected when we made the first discovery of a phenomenon or object. (By the way, this “serendipity” is found everywhere in science, but of course we are talking about astronomy here.)
There are arguments for why life (or the basis for life) as we know it works and might be common. This is certainly a bias based on what we know – but scientists try to be aware of these biases and correct for them (possible to a greater or lesser degree); fundamentally this is the basis for – and goal of – the scientific method. That being said, could there be forms of life based on something completely different than what we have here on Earth? Absolutely. I would not expect them to be undetectable to instruments, however (at least eventually: Technology improves, the questions we ask improve, and our understanding of the universe improves).
Statements like this....
Many things that aren't hard science are labeled as "theories" (e.g. Multiuniverse Theory) that aren't appropriately objective-based but may have some associated elegance in the math that suggest them. Do you have concern that things like today's increase in social media, etc. may erode, somewhat, the importance needed to be place in the SM (Scientific Method)?
...are a treat to read as it shows respect for the heart of science where proofs are for math and falsifications for theories and hypotheses.DrJoePesce said:
Many things that aren't hard science are labeled as "theories" (e.g. Multiuniverse Theory) that aren't appropriately objective-based but may have some associated elegance in the math that suggest them. Do you have concern that things like today's increase in social media, etc. may erode, somewhat, the importance needed to be place in the SM (Scientific Method)?
If there was Water on mars how come the rovers have not found caves?
Thanks Helio!
I don’t think social media is necessarily eroding the importance of the scientific method. Social media is a communication tool, and an additional source of information. I think social media just makes how we interpret information even more important and requires even more critical thinking when we evaluate the veracity of information (especially large volumes of information, and information that arrives to us rapidly). We then (I think) need to apply the scientific method in order to solve problems (and I maintain even everyday problems, not only scientific ones), and this is now even more important than ever.
Mentioning of “theory” gives me another topic: In everyday English, we tend to minimize what “theory” means – we say things like “It’s JUST a theory”. In science, when something becomes a theory, it has withstood repeated attempts at falsification, it’s been modified so that it explains nature very accurately, it is well on its way (if not there) to becoming a law: The theory of gravity is really the law of gravity; the theory of relativity; etc. On the contrary, in science when we have a new idea how something in nature works, an initial GUESS, we use the term “hypothesis” (that bright, hot, orb I see rising in the Eastern sky every morning might be a guy pulling a wagon load of hot coals). After those hypotheses are tested but withstand falsification – after lots and lots of tests - they can become a theory. So, we SHOULD be saying “it’s JUST a hypothesis”, not “JUST a theory”. The problem is, because of language, the meaning of theory has become minimized and people believe “theory” is closer to guess than to law. And this affects how they think of theories in science.
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