Explained - Blog Posts

It just kills me when writers create franchises where like 95% of the speaking roles are male, then get morally offended that all of the popular ships are gay. It’s like, what did they expect?

yo quiero que ustedes sepan que “Alex” es como un AU que he echo de Onceler😭💀 siento que ustedes suponen que es otro Alex o no se por que aún no he explicado nada😭🙏🏻//

I want you to know that “Alex” is like an AU that I made from Onceler😭💀 I feel like you assume it's another Alex or I don't know why I haven't explained anything yet😭🙏🏻

This phenomenon is something I'm sure everyone faces everyday!! Like when I wake up in the morning my mom looks like she is the happiest person to ever exist, laughing, smiling, joking and even does some of my chores!! But as the day progresses, my mom's mood worsens and soon it's time to go to bed, and she looks like me as if I'm the worst criminal on this Earth ToT. Don't be mistaken, I love my mom. BUT SOMEONE PLEASE EXPLAIN THIS PHENONEMON!!

Hi.dr.naomi.i have 2 questions.

1.Can this JAMES WEB T.S able to see Mercury, Venus and certain stars that are close to the sun either. I.

2.Why is the James Webb t.s.mirror yellow?

Any specific reason for this

Will it take pictures of Pluto?

When will we start seeing images from the James Webb telescope??

Does Webb have resolution to look more closely at nearby objects, like Mars or even Earth? Or just far things?

How exactly will it work? And whats the goal of the project?

Do you have any protections against asteroids?

Concerning the new telescope -out of curiosity- what is the maximum distance it can view planets, galaxies, objects, anything up to -in terms of common/metric measurement, and/or years (if applicable) etc.? -Rose

What does “chemical fingerprints” mean? What chemicals indicate possible life on other planets?

Will the James Webb Telescope also be able to spot out signs of life on habitable worlds?

Questions coming up from….

@maybeinanotherworld: JWST IS HAPPENING! How are all of you feeling about this?

@Anonymous: How powerful is this telescope, exactly?

@Anonymous: Why are the mirrors on it yellow?

@foeofcolor: How long is this estimated to last for? Like how long will it be able to function in space by estimates?

Black Holes Dine on Stellar Treats!

See that tiny blob of light, circled in red? Doesn’t look like much, does it? But that blob represents a feast big enough to feed a black hole around 30 million times the mass of our Sun! Scientists call these kinds of stellar meals tidal disruption events, and they’re some of the most dramatic happenings in the cosmos.

Sometimes, an unlucky star strays too close to a black hole. The black hole’s gravity pulls on the star, causing it to stretch in one direction and squeeze in another. Then the star pulls apart into a stream of gas. This is a tidal disruption event. (If you’re worried about this happening to our Sun – don’t. The nearest black hole we know about is over 1,000 light-years away. And black holes aren’t wild space vacuums. They don’t go zipping around sucking up random stars and planets. So we’re pretty safe from tidal disruption events!)

The trailing part of the stream gets flung out of the system. The rest of the gas loops back around the black hole, forming a disk. The material circling in the disk slowly drifts inward toward the black hole’s event horizon, the point at which nothing – not even light – can escape. The black hole consumes the gas and dust in its disk over many years.

Sometimes the black hole only munches on a passing star – we call this a partial tidal disruption event. The star loses some of its gas, but its own gravity pulls it back into shape before it passes the black hole again. Eventually, the black hole will have nibbled away enough material that the star can’t reform and gets destroyed.

We study tidal disruptions, both the full feasts and the partial snacks, using many kinds of telescopes. Usually, these events are spotted by ground-based telescopes like the Zwicky Transient Facility and the All-Sky Automated Survey for Supernovae network.

They alert other ground- and space-based telescopes – like our Neil Gehrels Swift Observatory (illustrated above) and the European Space Agency’s XMM-Newton – to follow up and collect more data using different wavelengths, from visible light to X-rays. Even our planet-hunting Transiting Exoplanet Survey Satellite has observed a few of these destructive wonders!

We’re also studying disruptions using multimessenger astronomy, where scientists use the information carried by light, particles, and space-time ripples to learn more about cosmic objects and occurrences.

But tidal disruptions are super rare. They only happen once every 10,000 to 100,000 years in a galaxy the size of our own Milky Way. Astronomers have only observed a few dozen events so far. By comparison, supernovae – the explosive deaths of stars – happen every 100 years or so in a galaxy like ours.

That’s why scientists make their own tidal disruptions using supercomputers, like the ones shown in the video here. Supercomputers allow researchers to build realistic models of stars. They can also include all of the physical effects they’d experience whipping ‘round a black hole, even those from Einstein’s theory of general relativity. They can alter features like how close the stars get and how massive the black holes are to see how it affects what happens to the stars. These simulations will help astronomers build better pictures of the events they observe in the night sky.

Keep up with what’s happening in the universe and how we study it by following NASA Universe on Twitter and Facebook.

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Hubble’s Guide to Viewing Deep Fields

They say a picture is worth a thousand words, but no images have left a greater impact on our understanding of the universe quite like the Hubble Space Telescope’s deep fields. Like time machines, these iconic images transport humanity billions of light-years back in time, offering a glimpse into the early universe and insight into galaxy evolution!

You’ve probably seen these images before, but what exactly do we see within them? Deep field images are basically core samples of our universe. By peering into a small portion of the night sky, we embark on a journey through space and time as thousands of galaxies appear before our very eyes.

So, how can a telescope the size of a school bus orbiting 340 miles above Earth uncover these mind-boggling galactic masterpieces? We’re here to break it down. Here’s Hubble’s step-by-step guide to viewing deep fields:

Step 1: Aim at the darkness

Believe it or not, capturing the light of a thousand galaxies actually begins in the dark. To observe extremely faint galaxies in the farthest corners of the cosmos, we need minimal light interference from nearby stars and other celestial objects. The key is to point Hubble’s camera at a dark patch of sky, away from the outer-edge glow of our own galaxy and removed from the path of our planet, the Sun, or the Moon. This “empty” black canvas of space will eventually transform into a stunning cosmic mosaic of galaxies.

The first deep field image was captured in 1995. In order to see far beyond nearby galaxies, Hubble’s camera focused on a relatively empty patch of sky within the constellation Ursa Major. The results were this step-shaped image, an extraordinary display of nearly 3,000 galaxies spread across billions of light-years, featuring some of the earliest galaxies to emerge shortly after the big bang.

Step 2: Take it all in

The universe is vast, and peering back billions of years takes time. Compared to Hubble’s typical exposure time of a few hours, deep fields can require hundreds of hours of exposure over several days. Patience is key. Capturing and combining several separate exposures allows astronomers to assemble a comprehensive core slice of our universe, providing key information about galaxy formation and evolution. Plus, by combining exposures from different wavelengths of light, astronomers are able to better understand galaxy distances, ages, and compositions.

The Hubble Ultra Deep Field is the deepest visible-light portrait of our universe. This astonishing display of nearly 10,000 galaxies was imaged over the course of 400 Hubble orbits around Earth, with a total of 800 exposures captured over 11.3 days.

Step 3: Go beyond what’s visible

The ability to see across billions of light-years and observe the farthest known galaxies in our universe requires access to wavelengths beyond those visible to the human eye. The universe is expanding and light from distant galaxies is stretched far across space, taking a long time to reach us here on Earth. This  phenomenon, known as “redshift,” causes longer wavelengths of light to appear redder the farther they have to travel through space. Far enough away, and the wavelengths will be stretched into infrared light. This is where Hubble’s infrared vision comes in handy. Infrared light allows us to observe light from some of the earliest galaxies in our universe and better understand the history of galaxy formation over time.

In 2009, Hubble observed the Ultra Deep Field in the infrared. Using the Near Infrared Camera and Multi-Object Spectrometer, astronomers gathered one of the deepest core samples of our universe and captured some of the most distant galaxies ever observed.

Step 4: Use your time machine

Apart from their remarkable beauty and impressive imagery, deep field images are packed with information, offering astronomers a cosmic history lesson billions of years back in time within a single portrait. Since light from distant galaxies takes time to reach us, these images allow astronomers to travel through time and observe these galaxies as they appear at various stages in their development. By observing Hubble’s deep field images, we can begin to discover the questions we’ve yet to ask about our universe.

Credit: NASA, ESA, R. Bouwens and G. Illingworth (University of California, Santa Cruz)

Hubble’s deep field images observe galaxies that emerged as far back as the big bang. This image of the Hubble Ultra Deep Field showcases 28 of over 500 early galaxies from when the universe was less than one billion years old. The light from these galaxies represent different stages in their evolution as their light travels through space to reach us.

Step 5: Expand the cosmic frontier

Hubble’s deep fields have opened a window to a small portion of our vast universe, and future space missions will take this deep field legacy even further. With advancements in technologies and scientific instruments, we will soon have the ability to further uncover the unimaginable.

Slated for launch in late 2021, NASA’s James Webb Space Telescope will offer a new lens to our universe with its impressive infrared capabilities. Relying largely on the telescope’s mid-infrared instrument, Webb will further study portions of the Hubble deep field images in greater detail, pushing the boundaries of the cosmic frontier even further.

And there you have it, Hubble’s guide to unlocking the secrets of the cosmos! To this day, deep field images remain fundamental building blocks for studying galaxy formation and deepening not only our understanding of the universe, but our place within it as well.

Still curious about Hubble Deep Fields? Explore more and follow along on Twitter, Facebook, and Instagram with #DeepFieldWeek!

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