To get out of the earth’s clutches, we need to travel at least at 11.2 km/s also called the escape velocity.
Similarly, since the gravitational strength of a black hole is so strong, the escape velocity ( if you intend to leave it ) exceeds the speed of light.
Where does it gets it’s gravitational powers?
To understand this, let’s do a thought experiment: What would happen if we compress earth to half its present radius without changing the mass density?
The gravity at the surface would be four times more because of the “inverse square law”. It gets stronger at shorter distances.
And now, say you keep on decreasing the radius even further, the gravity would just keep on spiking to phenomenal levels. This is the secret to the Black Holes extraordinary gravitational powers.
How are they even formed?
All stars follow a life cycle. I will elaborate on the life cycle in another post, since its kind of long. But this illustration from sciteachers would do for now:
Upon reaching a certain critical density, a star will collapse on its own weight. i.e Its radius will keep on decreasing and gravity swooping up at each stage untill it collapses to an almost infinitely small pinpoint.
And that’s how black holes are formed and why they have such a huge gravitational pull on Objects.
Hope you learnt something new about blackholes in this post. This is a series and we will dig deeper as we move down the line. As they say- tiny drops make a mighty ocean. Small baby steps at a time everyday and at the end we will attain colossal clarity! Have a good one.
The Andromeda galaxy, M31, is moving towards the Milky Way at a speed of 250,000 miles per hour and is predicted to collide, and eventually merge with our own galaxy in 4 billion years. The series of images above illustrates this merging of the two galaxies.
Im sure you’ve seen the post or heard the quote “when you wish upon a star, technically that star is a million light years away and it’s already dead, just like your dreams”
This is false. That star is not dead, it is not millions of light years away! the Milky Way galaxy is 100,000 light years across, so the oldest light reaching us from a star in our galaxy would be less than 100,000 years old (because we aren’t on the very edge). Stars live for millions and billions of years! Sure that supernova we viewed from another galaxy is from a star that had been dead for ages, but the stars you see at night are much closer and very much still burning brightly!
The light you are seeing of a star is old, but the star itself is not dead and neither are your dreams!
-this has been a slightly uplifting rant by janestreetdog (who is peeved by this misconception)
When a star wanders too close to a black hole, intense tidal forces rip
the star apart. In these events, called “tidal disruptions,” some of the
stellar debris is flung outward at high speed while the rest falls
toward the black hole. This causes a distinct X-ray flare that can last
for a few years.
NASA’s Chandra X-ray Observatory, Swift Gamma-ray Burst
Explorer, and ESA/NASA’s XMM-Newton collected different pieces of this
astronomical puzzle in ASASSN-14li. The event occurred near a
supermassive black hole estimated to weigh a few million times the mass
of the sun in the center of a galaxy that lies about 290
million light-years away. read more here
Pluto Has A Blue Sky New Horizons snapped this stunning photo of Pluto’s haze layer, revealing itself to be blue in color. The atmosphere is backlit by the sun and the layers of haze are several times higher than initially thought. Sunlight-initiated chemical reactions of nitrogen and methane are believed to be involved as the likely source of the haze. Image Credit: NASA/JHUAPL/SwRI
Astronomers lead interesting and quite exciting, lives.
I frequently get questions regarding the work environments, job prospects and pay. If there’s any part of you that yearns for the night sky and if you want to know what’s out there… perhaps this post can help you figure out if this is the path for you.
Astronomers, as you may know, use science and mathematics to unwrap the mysteries of the cosmos.
Do we live in a multiverse?
Are we alone?
Where do we come from?
These are examples of some of the large problems astronomers slowly chip away at. The work is philosophically and intellectually rewarding.
So what exactly does this work entail? Where do astronomers actually work?
(Image credit: Department of Energy)
Lectures are a regular part of the job description for many astronomers.
It’s a constant battle to ensure that the next generation is educated in STEM fields to ensure a vibrant world.
Many astronomers teach things from basic physics classes (often to a diverse student body of engineering, physics and biology students as an example) to astrophysics classes. Being able to communicate and present to large groups of people is important.
Not everything these folk do is lecture though. Astronomers do research too though and this research can be quite involved:
(Image credit: Keith Vinderlande)
(Image credit: W.M. Keck Observatory)
The above two images show the South Pole Telescope and the Keck Observatory respectively.
If you want a job that involves travel and adventure, you’ll almost certainly get both in this field. You may find yourself living in Arctic conditions for months in a night that never ends (seemingly). Whenever you go outside you might look up to the Southern Lights or the Milky Way.
Perhaps you’ll find yourself climbing the largest volcano on Earth, Mauna Kea, on your way to the famous Keck observatory. When you’re not observing you’d be spending your days below in Hawaii (and who wouldn’t like that?).
Some lucky astronomers find jobs at places like research laboratories (like NASA Ames or ESTEC in the Netherlands for example) where they get to spend the vast majority of their time on research.
Sometimes these sorts of jobs can involve working on projects that ultimately forward the work of astronomy without directly being astronomy itself:
(Image credit: NASA)
Plenty of people get their education in astronomy but end up helping groups like NASA, ESA or SpaceX build future robots and spacecraft to explore the universe.
Excitingly, we now live in a time where small startups are being founded to further private enterprise in space: companies are looking into mining asteroids, building tourist spacecrafts and inflatable space stations. Anyone with the right knowledge and motivation can be a part of this amazing new space race.
So what exactly does this workload usually entail? Well typically astronomy work involves lots of math. This is our tool to unravel the mechanics of space and time.
You’ll be using calculus pretty regularly and your education will need to prepare you for it. Usually astronomers get their Bachelor’s degree in physics and then their PhD in astronomy. Some go slightly different routes but that’s the norm.
In addition to math, astronomers learn how to program so that they can send certain complicated problems to be crunched by the massively powerful capabilities of modern computers.
In fact, astronomers get so well-practiced in computer programming that if they were to ever get tired of the world of academia and research, it’s quite easy for an astronomer to get a relatively cushy position as a programmer (I love repping that some even get jobs as Disney animators).
Over all, if you want to be an astronomer expect to spend lots of time at a computer and working out math problems. Expect to stand in front of groups every now and then to present research or teach a class and lastly… be willing to get your hands dirty. You will almost certainly do some traveling. As you saw above, many observatories are located in exciting and exotic places.
When it comes to working from your computer (which you’ll be doing often as an astronomer) there’s the cushy fact that this can often be done wherever you get an internet signal.
If you decide to go for the (often better paying) work as a software engineer, the same often applies.
You’ll be able to make your own schedule more often than other jobs and you’ll see and learn more about the world and universe than almost any other job there is. Astronomy is a rewarding profession that demands quite a lot from you, but gives back in spades.
Good luck on your path to the stars!
(Top image credit: Alan L, Eric Hill and NASA respectively)