What is the largest object in the universe?

 A question of how big something can be.

When speaking about the biggest object in the universe, you must always remember galaxy IC-1101.

Why don’t we see how big it actually is?

Milky Way:

Our galaxy, the Milky Way, is 100,000 light-years across, with an estimated 400 billion stars in it. 100,000 light-years would be 1,000,000,000,000,000,000 kilometers across. Now, let’s see how long it would take you, to cross it, with humanity’s fastest spacecraft. Let’s start with the math. As stated earlier, the Milky Way galaxy is 100,000 light-years across, each light-year is approximately 6 trillion miles, and for us to cross just one light-year, it would take us nearly 20,000 years with humanity’s fastest spacecraft New Horizons. Unrealistically, It would take you a wopping 2 billion years to cross our own galaxy with the fastest thing we have.

Andromeda:

The Andromeda galaxy has more than twice the amount of stars than our galaxy has (one trillion to be exact), and is 2.5 million light-years away from Earth. Now, this galaxy is about 140,000 light-years across, compared to 100,000 light-years the Milky Way. Doing the same math, it would take you 2.8 billion years to cross it with the exact same spacecraft, without adding the time it would take you to get there.

Now here ‘s where things get big:

IC 1101:

This galaxy is approximately 1.2 billion light-years away from Earth. It has 100 trillion stars, making literally a dot of the Milky Way, and the Andromeda Galaxy. This galaxy is 50 times the size of the Milky Way, and 2,000 times as massive. Doing the math, it would take us a mind-boggling 100 billion years to cross that galaxy. I must confess I was getting pretty excited while making this answer.

We are as tiny as we can get.

What is the difference between the object in the upper part and the one in the lower part of the image?

 None! Both actually show NGC 1566, a magnificent spiral galaxy about twenty million light-years from Earth in the Dorado constellation. What changes between the two parts of the photo is the observation wavelength. The upper part of the photo was obtained in the visible spectrum by the Hubble Space Telescope, showing how the galaxy would appear to our eyes if we were located nearby. The lower part, on the other hand, shows NGC 1566 captured in the infrared by the James Webb Space Telescope. The Hubble photo allows detailed recognition of the structure of NGC 1566. At its center lies a small nucleus composed of old yellow stars. Two powerful spiral arms extend from it, containing young blue stars and pink stellar regions. Dust is also visible, appearing dark brown as it blocks the light from the background stars. In the image obtained by the James Webb, both the young blue stars and the star-forming regions have disappeared. The spiral arms are now outlined by the dust, shown in red, which is the true protagonist of the shot as it emits most at these wavelengths. The stars in the nucleus are still visible, but their brightness is nothing compared to that of the dust.

THE NGC 1566 GALAXY CAPTURED BY WEBB AND HUBBLE!

Credit: NASA, ESA, CSA, STScI, J. Lee (STScI), T. Williams (Oxford), R. Chandar (UToledo), D. Calzetti (UMass), PHANGS Team.

What is a possible explanation for Punctum, the newly discovered space object?

 

Punctum might be a brand new mysterious astronomical object that has never been observed before

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We discovered it with the ALMA radiotelescope, which was observing the active galactic nucleus of the nearby galaxy NGC 4945, 11 million light-years away, shown above. This enigmatic pointy source of millimeter-range highly polarized electromagnetic radiation was discovered by accident because it showed in the field of view.

We don’t know what it is, but it must be very small to emit radiation that is polarized, which is usually produced by objects with a very strong magnetic field, like magnetars. Except that this one emits radiation four to five orders of magnitude more powerfully than any known magnetar (10,000 to 100,000 times) and even 10 to 100 times stronger than supernovas.

It’s not a transient source of radiation like these powerful explosions because it has been continuously observed since 2023. Furthermore, it’s not visible in visible light or other ranges of electromagnetic radiation.

We can only guess what it is. Maybe it’s a very powerful magnetar that is located in an unusual environment that made it so powerful. This signal cannot come from a remnant of a supernova because they are too large to emit such a powerful polarized radiation.

Perhaps if we find more of these mysterious Punctums elsewhere, we might finally figure out what it is.

What is the most mysterious object in our galaxy?

 It’s hard to say what’s the absolutely most mysterious, but the first thing that comes to mind is Eta Carinae.

The star (or stars - it appears to be a multi-star system) is among the brightest in the galaxy, with the primary component more than 5 million times brighter than the sun. At 7,500 light years away, it’s one of the most distant stars we can see without a telescope, and was the second brightest star in the night sky for a few days in March 1843.

Eta Carinae’s main component is highly active, and spewed a huge eruption of material in the mid-1800s. It was this eruption that made it so bright. It then faded so much that for a while a telescope was needed to see it. Now it’s visible again with the naked eye.

Scientists think it’s likely to explode in a supernova sometime in the near future (astronomically). That means anytime between now and say, 3 million years from now. If it does, it will be one of the brightest objects in our sky for a short period. Probably five times brighter than the planet Venus.

Despite its great distance, it might be one of the most dangerous objects in the sky, because it’s likely to be massive enough to explode as a “hypernova,” Some scientists predict it could strip the Earth of its ozone layer, something that wouldn’t normally happen unless a supernova were within 50 light years of Earth.

The Eta Carinae system is seen below. The material expelled from it during its eruption in the mid-1800s is quite evident. It’s this material that caused the star to fade in brightness from our vantage point for a while, as the material hid the star.

If the sun suddenly became as luminous as Eta Carinea (this can’t happen), the Earth’s entire surface would melt, mountains and all.

If a black hole loses enough energy, does it become another cosmic object?

 

${10}^{67}$.

That's how long you'll have to wait and find out.

One hundred trillion trillion trillion trillion trillion years. Or,

10,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000.

You see, that's how long it takes for a black hole the size of our sun to evaporate.

Hawking radiation, that's the ticket.

The black hole slowly leaks particles, losing mass, until poof, it's gone.

What happens next?

Does it turn into a star? A nebula? A cosmic quesadilla?"

Well, not exactly.

The thing about black holes is they're not like other cosmic objects. They're not made of stuff, per se.

They're more like...holes in the fabric of spacetime.

But, and this is where it gets interesting, as the black hole evaporates, it might leave something behind.

Not a star or a gas cloud, but a concentrated nugget of pure information. This is a mind-bender, even for physicists.

Some think this information could be the key to understanding the universe's deepest secrets, while others think it might just disappear into the ether.

There's a theory floating around about a black hole remnant. Something left behind when a black hole evaporates.

Not a star, not a cloud, but a nugget of pure information. This nugget, the theory goes, might be the key to unlocking some of the universe's most tightly held secrets.

It's a long shot, a cosmic gamble, but that's the kind of stuff that keeps us stargazers up at night.

It's the mystery, the unknown, the sheer audacity of the universe that keeps us reaching for the stars, even when they're a hundred trillion trillion trillion trillion trillion years away.

What is the biggest single object in the observable universe?

 The biggest single object (not counting galaxies, universe, etc.) ever discovered is S5 0014+81. Prepare to have your mind blown.

S5 0014+81 is a quasar. Upon further inspection they found out that a black hole resides at the center of the quasar. Scientists were expecting an average sized black hole… but were surprised to find out that the mass of the black hole was a massive 40,000,000,000 (40 Billion) Solar Masses.

*Waits 5 seconds to let that sink in*

The Schwarzschild radius of that superheavy black hole is 118.35 Billion Kilometers.

Doesn’t sound like much, eh? Well, here is the thing: If our sun were the size of a soccer ball, “big bro’s” diameter is 37.42km.

Here is another picture to help you deal with the size of this object: