FastFourierTransform wrote:Source of the post EDIT: Dammit! I've been flashed by Watsisname once again
Your posts are so worth waiting for though. You always manage to find the coolest media to go with them!
FastFourierTransform wrote:SHORT ANWER:
You have probably witnessed the launch of Chandrayaan-2 spacecraft (the last stages of the launch litted by the Sun). The Indian spacecraft is headed towards the Moon and carries a Lander and a Rover for the Lunar South Pole!
Supernovas are not so easy to spot in principle. The last time we saw a supernova with the naked eye was 415 years ago and the last one that happened in our galaxy was 151 years ago (we didn't register it when it occurred sadly but we have backpropagated the motion of its remanent shell of gas and dust now that we have discovered it). To be seen with the naked eye it is in principle necessary for them to be located in our galaxy. As you can see they are fairly unfrequent. The current estimated rate is of 4.6 supernovas per century but this is considered to be optimistic and the even then the majority of them wouldn't be visible to the naked eye (due to them happening in dust-obscured regions of the galaxy).
The chances are lowered if you observed it close to Izar. Bootes is very close to the North Galactic Pole, which is located in Coma Berenices. This means that you are watching almost perpendicularly with respect to the galactic plane. Since the vast majority of stars in our galaxy concentrate on the plane, having a high latitude supernova makes it even more improbable. The chances for that are extremely small. I've labeled this chart to show you the location of the galactic plane.
Could it be an extragalactic supernova? A supernova in some other nearby galaxy? As I said, those would be very dim. There is an updated list of all the recent detections and today there haven't been any detections by any instrument. Yesterday 21 there were 2 detections made by the Asteroid Terrestrial-impact Last Alert System but 1) it was yesterday, not today 2) both are no way near Bootes and 3) Their brightness was of 17.3 mag and 18.7 mag, which is so dim you wouldn't expect to see them even with a semi-professional observatory.
Also, supernovas are point-like sources with no details nor extension as seen from Earth (unless you are just a few light years away in which case we would be dead) and not "hazy with non-distinct shape". We therefore should seek other possible explanations.
A flash associated with a GRB?
Gamma-ray bursts are complex phenomena that still largely need explanation. Associated with the gamma-rays there can be a visible counterpart. In some cases the GRBs have even be visible with the naked eye. A good example is GRB 080319B, which was detected by the Swift satellite in 2008. At its peak brightness GRB 080319B reached 5.8 mag (just barely visible but visible in dark sky areas). It was visible for 30 seconds (in the same order of magnitude as your source). The object was located on the other size of the universe, 7.5 billion light years away! (this is in fact the farthest object ever seen with the naked eye).
A closer GRB could be brighter and the afterglow could be visible for more than a minute so this matches some of your parameters. Let's see if there is some detection for today or yesterday; The last time the automated system of the Swift satellite triggered was 3 days ago and it didn't happened in Bootes. The Fermi telescope automated system triggered 8 times two days ago but since then there haven't be any. INTEGRAL was triggered yesterday (not today) but in a completely different region of the sky. The last trigger of MAXI, installed on of the ISS, was 4 days ago. Since these lists are updated in real-time and due to the differences in the date with respect to your observation I would say that if yours was a GRB it wasn't detected by any instrument. If you saw it with the naked eye it means that it probably should have been detected by some of those telescopes at the moment.
Even if you had luck and no instrument detected the highly luminous flash that you saw with your naked eye a GRB still doesn't match the "hazy thumbprint type of bright white haze about the same size as the moon" description. GRBs like supernovae are point-like sources as seen from Earth.
A meteor/bolide moving in your direction?
I know very little on this topic so it might be nice to have midtskogen's opinion on this (since he has an observatory dedicated to meteor detection and is part of a larger network of observers).
A meteor is a bright event but it moves across the sky. I don't think it can endure for as much as a minute in any case and for it to be still you would need to have it moving in your direction (which is excedenly improbable). The only match I see is the brightness and the possible non-point-like shape since it could look like a small trail or, if it fragmented in the upper atmosphere, like a small cloud. But again, it looks like we need to tune the parameters too much to match your expectations and even then I doubt I'm correctly predicting what it would look like.
A satellite flare?
Flares are quite spectacular phenomena. I reccomend you to plan some observation to look for them. Satellites are rotating in space and also their relative configurations with respect to the Sun and Earth change as they move in their orbits. Iridium satellites (some communication satellites that are located in LEO) have large panels that in certain occasions reflect sun-light directly into some spot on the surface of Earth, as they angle correctly by chance for that. You see them as a star appearing out of nothing and increasing to brightnesses that match that of the brightest star or even more in a matter of seconds. They can last for even a minute if you are lucky. iridium satellites display the most notable flares (they are reflective and nearby), butthere is no Iridium flare prediction for that location at that time apparently.
There are two problems here. They are point-like again and they move (not significantly but noticiably for sure). We live under an atmosphere so a "hazy" appearence should give you a hint; A small isolated cloud aligned in that direction could explain the hazy appearence of the light (even if it was a clear night there's always some small isolated clouds that one can't spot in many cases due to the darkness of the night). If you find a cloud to be something improbable think about the fact this observation was certainly unfrequent (at least for you) so it might be explained by common factors but in unfrequent dispositions. It looks like it was indeed clear at the moment but still small clouds can form
Also the movement of the light could be reduced if the flare was yielded by a Geostationary satellite instead of an Iridium satellite. Let's search our candidates. Using a free software called Heavensat updated with the satellites orbital parameters of today we can see which objects where near Izar (a more specific separation from it would help) at 7:45 pm (a more specific date would help) as seen from Nyngan (a more specific location could help refine this). Here I've selected only high-altitude satellites (since LEO satellites would move to fast in the sky for them to be seen as still).
As you can see the geostationary satellites are located in a belt close to Bootes but to far away to be our candidate sources (also flares from geostationary satellites are very dim). Izar is marked with the green circle. But moving the slider for 2 minutes before and 2 minutes after 7:45 pm there are two candidates close to Izar that barely move (one of them moves in the same direction as the rotation of the sky so the relative distance to Izar is mantained). Both would look almost still for a naked eye observer for a span of 1 minute.
The first candidate is BREEZE-M R/B 2017-057B which is the upper stage of a Russian rocket that launched ASIASAT 9 (a geostationary satellite). This upper stage of the rocket is orbiting Earth uncontrolled at an altitude of 32.600 km.
And the second candidate is FREGAT R/B 2011-060C which is also the upper stage of a Russian rocket. This rocket launched ESA's satellite GAL E11 (part of the Galileo constellation). It's orbiting Earth uncontrolled at an altitude of 23.600 km. Since it is a big object and it is closer than BREEZE-M R/B 2017-057B we should expect him to yield the largest flares of them both.
But again satellite flares at that altitude shouldn't be very bright except for some special cases and satellite flares are still point-like in general (as you can see astrophysical phenomena that can be seen with the naked eye are usually point-like in shape).
An airplane with the headlights directed to you?
It might sound stupid but we are not as familiar with airplane lights as we might think. When airplanes are headed towards us the directional navigation lights increase a lot in brightness. This surprises the first few times you see it (which is not as common as we think). Many times it has been so unfamiliar that it has been announced as a UFO. Also, in this situation the source of light might appear to not move at all. When we are not directly lighted (because of the plane making a turn for example) it vanishes quickly.
Let's check if there was an airplane coming at 7:45 pm from the North to Nyngan. As you can see there were two airplanes: A huge Airbus A330-343 with ID PAL213 from Manila to Sydney and a large Boeing 737-838 with ID QF705 from Cairns to Melbourne.
The problem is that both airplanes are very far away or do not point directly into Nyangan's surroundigns when they are closer some minutes later. At that distance with those elevations both should have appeared at 2º - 3º above the horizon (which could explain the haze) and Izar is way higher in the sky (at 30º). Overall the area is an airplane dessert, there is little air traffic there so I think this is not a plausible explanation either.
A rocket launch?
As Watsisname has said a plausible explanation is a rocket launch. The different stages of the rocket can be litted by the Sun way after sunset and the exhaust looks just like a very interesting haze in the sky for some minutes.
There has been a launch today! A Geosynchronous Satellite Launch Vehicle Mark III (a rocket with 3 stages) has launched the Chandrayaan-2 mission to the Moon. It has been launched from Satish Dhawan Space Centre in India. It was launched at 7:13 Sydney Time (half an hour before your observation).You can watch the entire launch here
From the video I took a screenshot of the ground trace of the object some minutes after launch. I can recognize Sri Lanka's shore in there. With that we can estimate the flight path.
This is a very rought propagation (done by eye) of the trajectory shown in the monitors of the control room. But as you can see it extends roughtly to Australia. Half an hour seems a totally right time for that to arrive there.
This I think is the most probable situation. You saw the launch of Chandrayaan-2 on its way to the Moon. Maybe tomorrow we have some video records on YouTube of witnesses like you.
Albrecht wrote:Did you know that you can make your own supernova? The University of Oxford scietists showed the whole process. Can't find the article by Phys (dot) com research paper writer though. They did it using powerful lasers. The research results were displayed at the Royal Society Summer Science Exhibition, if I'm not mistaken.
longname wrote:Source of the post Are you sure you're not thinking of fusion?
A-L-E-X wrote:Source of the post Isn't there a way to emulate black hole effects too, by creating artificial black holes in a lab?
Watsisname wrote:Source of the post Analogues of black holes (in particular, demonstrating effects analogous to event horizons) can be made with fluids.
Watsisname wrote:A-L-E-X wrote:Source of the post Isn't there a way to emulate black hole effects too, by creating artificial black holes in a lab?
Absolutely. Analogues of black holes (in particular, demonstrating effects analogous to event horizons) can be made with fluids. Set up a fluid flow where within some region the flow speed is faster than sound in that fluid, and you have a "sonic black hole", shrouded with an event horizon for sound signals instead of light signals. Experiments like these can also be useful for understanding Hawking radiation, and other black hole behavior.
In fact, making an analogue black hole is almost ridiculously easy. If you have access to a creek, try finding a location in that creek where the flow is forced between some large rocks and accelerated. Make some ripples there, and you may find places where the entirety of a ripple is swept downstream. That's analogous to being inside a black hole event horizon. Play around a little further and you might find a specific location where most of the ring of the ripple is swept downstream, but the part moving upstream is frozen in place. That's the event horizon, in the context of water waves.
Being very nerdy, I have of course tried this and it's a beautiful thing to see, but for completeness I should clarify that it isn't a perfect analogy, due to an unfortunate feature of water waves. They have dispersion, meaning waves with different wavelengths travel at different speeds. If you watch a series of ripples closely you'll find they are actually not a constant set of expanding rings, but rather a complex superposition of waves moving at different speeds. So in the "black hole creek" analogue, you won't really get all the ripples frozen on a horizon, but you should still clearly see an effect that is close to that.