Could black holes be shortcuts through space and time?

 Yes,it is theoretically possible but not in a practical way. According to GR, space and time are not two mutually independent dimensions but connected through space-time fabric.When an object of masses are there,it create space time curvature on that fabric. Since black hole have very high density ,so it creates an enormous amount of curvature.

Now, think space time fabric as a thin piece of paper,where by folding it in a way that two distant points are closed by a tiny tunnel (as here the width of the paper). This is possible also in a real case of space time geometry.And that tiny tunnel are shortcuts through space-time between two locations of the universe.

That tunnel(also known as worm hole) connects two different locations where one side is a black hole and opposite site there is a white hole.

Though this idea is highly speculative and it is believed that wormholes are highly unstable. It would be saying too much speculation that we could do time travel by that wormhole.

The deepest problem is that we have zero observational evidence that wormholes exist at all. They are valid solutions to Einstein's field equations, but mathematical possibility doesn't guarantee physical reality.

With the super clear cameras today, why are the photos from space vehicles so bad?

 I honestly can’t figure out what you are talking about.

Here is a picture of Europa taken by Voyager 2 almost 40 years ago. Quora can’t even show it in full detail.

In comparison, this is a Galileo picture of Europa from 25 years ago.

More recently New Horizons took this picture of Charon, the sister world of Pluto.

Keep in mind that the Sun’s light is so dim at Charon, it’s like taking a picture of the Earth with barely more than moonlight. (That is a little hyperbole. It’s more like a floodlit building at night. See the comment below.)

Maybe you are confused because pictures of gas giants do not look as detailed?

That’s a case of the picture is sharp, but Jupiter isn’t so sharp and contrasty, because, well, it is a nebulous gas that you are looking at.

Maybe it is Hubble pictures that you feel are not sharp.

Well, again, you are looking at a nebula.

Could you give an example of pictures from space vehicles that you do not think are clear?

Maybe you don’t like the Hubble Deep Field photos?

Keep in mind you are looking at a tiny patch of sky that has been magnified considerably. Also remember that before Edwin Hubble discovered that Andromeda was actually a galaxy, they were called “nebulae” because they appeared fuzzy.

Or maybe you thought this picture of the Earth taken from the International Space Station is not clear enough.

What are some of the most amazing facts about space?

 

1. The Sunrise that we see every morning on the earth is actually an illusion. The sun won’t actually be above horizon for the next 2 to 5 minutes of the sunrise time. Earth’s atmosphere bends the incoming sun rays like a lens or glass of water. So we see the image of the sun projected above the horizon before the physical sun is actually there.

Since, Sun’s light takes about 8 minutes to reach Earth. So, when we look at sun, we are actually seeing the sun as it was 8 minutes ago. So, sun is 8 light-minutes away from us.

2. The distance between Earth and Neptune varies as the planets orbit the Sun. The Sunlight takes about 4 hours to reach Neptune, on an average. So, Neptune will be 4 light hours away from us. We see Neptune as it was 4 hours ago.

The nearest Star to the Sun, Proxima Centauri is about 4 Light years away from Sun. NASA’s Voyager space craft moves at the speed more than 56,000 Km per hour. At this speed, it would take Voyager about 80,000 years to reach Proxima Centauri.

3. There are rogue planets in the space. These are the planetary bodies which have no gravitational influence of any Start on them. They roam freely around the galaxy.

Since they are not related to any star, there are ways, different from conventional ones, to find rogue planets.

Our Milky Way has billions of rogue planets.

4. The oldest galaxy that has been ever seen from earth is about 13.8 billion year old starlight as captured by Hubble telescope.

It is believed that it is created just 400 million years after the BIG BANG. When the light from that galaxy left for earth, there was no earth, no Sun.

5. If you compress all the cosmic activities since the beginning of time into one single year calendar, we humans, who are at the verge of every great technology breakthrough, are living in the midnight of December 31, 11:59:59, in the last second of the calendar. The January 1st is the beginning of Time.

6. The Earth is rotating at more than 1600 km per hour speed. While the Earth orbits the sun, it moves at more than 100,000 Km per hour. The Sun is moving through the galaxy at 500,000 miles per hour. The Milky Way is moving through the universe at about 1.5 million miles per hour. We have no fixed place in universe.

7. There was the scientist John Michell, who in 18th century put forward the idea of black holes. In his paper for Philosophical Transactions of the Royal Society of London, he mentioned the black hole as DARK STARS. He imagined a star so big, so massive that not even light could escape its gravitational pull. He also added that we can detect these dark stars by their extreme Gravity. TODAY, we call it a BLACK HOLE.

8. The first ever discovered black hole by us is CYGNUS X-1. It was discovered in 1964. No, we have nothing to worry about it. It is about 6000 light years far from our SUN. It is found by X-ray detection.

9. There is boundary that separates the black hole from the rest of the universe is called the EVENT HORIZON.

In general terms, it is the point of no return. When you reach or pass event horizon, even light cannot escape it. The light if present inside the boundary of event horizon can never reach the observer outside the event horizon.

10. A star about five times as massive as the Sun will undergo a much more violent collapse. The outer layers of the star will be ejected into space in a supernova explosion, leaving behind a collapsed star called a neutron star.

Stars collapse when their fuel is completely exhausted. It starts to collapse under its own gravity. At last it comes up to love upon its electron forces that held the black dwarf star. It’s radius varies and sometime they turn into black holes.

THANK YOU FOR READING

Ashutosh Sharma (आशुतोष शर्मा)

EDIT 1: Thank you for the response.

As asked by Pradeep Rajpoot I would like to add about what humans are doing to study the outer space.

VOYAGER 1: It is a space probe that was launched by NASA, to study the outer solar system. Voyager 1 was launched on 5th sepetember 1977 and has been in operation ever since(over 39 years).

It has traveled over 138 AU (over ) from Sun as of march 2017. During the extended mission of studying the outer boundaries of the solar system Voyager 1 crossed the Heliopause on August 2012.

In simple words, Heliosphere is the region of the solar system in which the Sun gravitational field can be felt. The edge of the Heliosphere is the called the Heliopause.

Image source: http://photojournal.jpl.nasa.gov/catalog/PIA17046

Voyager 1 has crossed heliopause and entered into Interstellar space.

Look at the pale blue dot in the picture in the slight right side of the picture. That’s us. THE EARTH. It was taken by voyager when it crossed 6 billion Km.

The mission is expected to continue till around 2025 because by then, the radioisotope thermoelectric generators will no longer supply enough power to operate any of the instrument of the probe.

The voyager 1 carries a golden plated audio visual disc if the probe is found by any other intelligent life forms on the other planetary systems. It carries the photographs of earth’s different life forms, some scientific information, greeting from Secretary-General of United Nations and President of USA. Different sounds of earth, sounds of whales, baby crying, collection of music. The record also contains greeting in 55 different languages.

IF you go through this link on the official site of Voyager, they are continuously updating the distance of the voyager from the earth and sun. Where are the Voyagers

THANK YOU FOR READING. WILL COME UP WITH SOME MORE INTERESTING FACTS SOON.

Ashutosh Sharma (आशुतोष शर्मा)

Image source: Voyager 1: Google

PALE BLUE DOT IMAGE: Voyager - The Interstellar Mission

GOLDEN DISC RECORD: Voyager - The Interstellar Mission

Would we see stars as ball shaped rather than star-shaped?

 Stars are pretty much perfect spheres.

The “star shape” isn’t “real” it’s due to diffraction. For telescopes - this happens due to the support structures holding up the mirrors - or the segmented mirrors in the case of telescopes that use multiple smaller mirrors rather than one big one.

With naked eye viewing, the effect is due to diffraction through your eyelashes (!!) - which is why the effect gets much bigger when you squint.

One cool “Pro-tip” to tell the difference between photos taken by Hubble and James Webb…is to count the number of “star bursts” around bright objects… these two photos are of the exact same patch of sky…

Aside from the fact that JWST is a whole lot sharper and brighter…

Hubble has four lines coming out of that bright star in the middle - which are due to refraction around the struts that hold it’s secondary mirror in front of the primary.

James Webb has six around the same star because is uses a bunch of hexagonal mirrors.

What are some of the most amazing facts about space?

 Some amazing space facts that I came across internet are as follow:

• If two pieces of metal touch in space, they will melt together and become one. It is something called “cold welding” or “contact welding”. This does not happens on earth because the atmosphere puts a layer of oxidised material between the surfaces which makes the welding processing impossible. This could seem like a big problem for satellites, space station in space but since the metals come from earth, they are already coated with the material.

• The sun is actually not yellow, it only appears yellow because of earth’s atmosphere. In reality sun outputs all colours in visible spectrum at almost equal intensity. Which means the true colour of sun is actually white.

• Stars can be weird. There is a star out there with the name Wise 1828+2650. But it’s not the name which is interesting but rather how cold it is. It is the coldest star ever found with a temperature range of -23 to -127 degree celsius. Another weird star is BPM 37093, the star core is made up of diamond (10 Billion Trillion Trillion carats to be precise). And Neutron stars are weirder, these stars are so dense that a single teaspoon of it’s material weigh over 100 Million Ton.

• In 2023, we might have a reality tv show on Mars. This if the Mars One project is successful which has a goal to set permanent colony on Mars. Out of over 200,000+ enteries, only 4 people will be selected who will be sent on and every step of the journey will be documented. Every 2 years additional colonist will be sent to set the further coloney (4 in 2023, 8 in 2025, 12 in 2027 and so on).

• Time on Earth moves faster than time in space. Time to melt your brain: all astronauts are time travelers. That's a fact! Why? Because the planet's orbit gives us Earthlings an extra second per week. It's called "time dilation" and it's one of the many contributions Albert Einstein made to the study of outer space.

• Outer Space smells unbearably awful. What does outer space smell like? It smells like it wants you to die. Imagine if you walked into a room that smelled like rum, sulfur, fried steak, burning metal, and raspberries.That's what outer space smells like. The universe is sending you a message: Go back to Earth - this place isn't meant for noses.

• There's a giant black hole hurtling through space at 3 million miles per hour. Let's not mince words: a supermassive black hole weighing in at millions (millions!) of times heavier than the sun is currently hurtling through space at roughly three million miles per hour. This particular black hole was ejected from its own galaxy and is roaming between galaxies, four billion light years away.

• Suppose a star is 100 light-years away from the Earth. Therefore, the light coming from the star (which carries its information) takes roughly 100 years to reach Earth. When we look at the stars, we are seeing them as they were years ago. If a star is 100 light years away, we are seeing it as it was 100 years ago, etc. If a star dies (goes nova), we won't know about it for the year-equivalent of its distance in light-years. Then, one day, we'll see a flash in the sky and we'll know that if it is 27 light-years away, the star died 27 years ago.

Source: Internet

Why don't we see other galaxies or even stars near us in space?

 By chance, mostly, we happen to be over 4 light years from the closest star and our galaxy isn’t that close to other galaxies. Beings on another planet around a different star in a different galaxy might have very different night skies, full of light, with little darkness in between objects from their point of view.

Even inside our galaxy, different worlds would see very different skies. A planet near the center of the Milkyway would have a sky crammed full of stars, separated by mere light weeks, instead of the average in our sector of 5 light years or so. We are much further from the center, about 2/3rds of the way out.

In our universe, galaxies are quite far apart. The light that reaches us on Earth has thinned out into very faint glows. Andromeda is pretty close to us as galaxies go. But it is still 2.4 Million light years away. If our eyes were sensitive enough we would see Andromeda clearly as the single dominant object in our sky. Here’s the Moon and Andromeda illustrated to show their relative sizes in our current sky:

Andromeda is actually way bigger than the Moon in our sky. But the light is too faint for us to really see it well. You CAN see it with your eyes if you know where to look, but it won’t look like much with just your eyes. Merely a faint smudge of light. And that is only possible if the sky is REALLY REALLY dark. The stars we see are much closer to us so their light is stronger, much stronger than the entire Andromeda galaxy from 2.4 Million miles away. Even a star 1000 light years from Earth is going to seem WAY brighter than the collection of stars in the Andromeda galaxy.

But nothing is permanent. Our sky will change dramatically over time.

The above shows a sequence of skies over Earth spanning several billion years. The merger will start in about 4.5 Billion years and the Andromeda and Milkyway will both be permanently distorted and altered. Eventually, we end up in some sort of elliptical galaxy with a sky blazing with stars.

But most of the universe is pretty uniform and spread out, with clumps of galaxies along strands of galaxy clusters and super-clusters. Because gravity clusters masses together and even causes galaxies to collide, the perception we currently have of everything being so far away won’t always be the case.

In the above Hubble image, you can see the results of two galaxies merging. The spiral arms get swept out in distorted shapes as the central regions of the galaxies try to merge into a more unified whole. This has happened countless times in our Universe and the above image is certainly not a rare case.

So regarding what we see in our sky, rest assured it won’t always be this boring. It just changes slowly, over billions of years.

I tend to think of our sky as boring. We live in the suburbs of our galaxy, nothing too interesting is clearly visible with our eyes. We need telescopes to look at the cool stuff in any detail. That said, even a modest pair of binoculars can reveal a lot of interesting objects and allow you to see way more stars than just your eyes can pick up on their own. There are a lot of stars in our sky. If we could see every star in our sky, it would look very different. But the light from more distant objects is typically weaker, so we just see black in between the brighter closer stars. But if we could just stand there, letting the weak photons from distant stars stack up in our eyeballs, we would see something like this:

The bright vertical band is the plane of our galaxy, and you can see dark dust lanes cutting through that light. More stars are visible here than you would see with your eyes. Photos like this leave the shutter open for several minutes to let the light accumulate.

So it is a matter of our perspective and the limitations of human eyes that give this impression that the sky isn’t full of light sources at night. We can reveal the truth of how full the universe really is by doing long-term exposures with cameras and by using telescopes. Of course, this is STILL a perspective. The universe is, in fact, mostly EMPTY. But if we can sample a large swath of the sky, we see a LOT of sources of light, most from objects in our galaxy.

If Andromeda is the closest galaxy to us, why have we not started exploring it yet?

 The nearest star beyond our own Sun is about four light-years away - or about 25 trillion miles. The farthest any man-made object has traveled from Earth (Voyager I) is currently 15 billion miles away. That is, Voyager I, launched in 1977, is about one sixteen hundredth of the way to the nearest star outside our Solar System … after nearly fifty years traveling in space. The Andromeda Galaxy is over 600,000 times as far away as that star. So that galaxy is about a billion times farther away than the most distant thing we have launched into space.

See all those stars in the photo below? They are all in our little section of the Milky Way galaxy. Every single one of those is many times farther away than Proxima Centauri (the nearest star I mentioned). That arrow locates the Andromeda Galaxy, which is about twice the size of our own galaxy, the Milky Way.

So maybe that’s the reason.

What are some of the most amazing facts about space?

 Scientists know about space in deep more then they know about oceans.

1. Space is around 13.8 billion years old. Scientists estimate that it would last another 5000 million years !

2. Footprint and tire tracks left on Moon will stay there forever, due to environmental conditions!

3. Sun makes a full rotation once every 27 days.

4. Chances of a person from earth being hit by space debris is 1 in 5 billion

5. There are approximately 200,000,000,000 stars in the Milky Way.

6. Largest star known to mankind is R136a1 which has mass of 265,320 times that of the sun !

7. Our moon is moving away from the earth at the rate of 4 cm per year.

8. Sun loses up to a billion kilogrammes per second due to solar winds.

9. In space the skin on your feet peels off!

10. Space is not that far away.

Space officially begins at the universal marker of the Karman Line. This invisible boundary is 100km above the Earth. In theory if you could drive your car upwards, you could be in space in less than hour.

Image source - astropics