Astronomers used three of NASA's Great Observatories to capture this multiwavelength image showing galaxy cluster IDCS J1426.5+3508. It includes X-rays recorded by the Chandra X-ray Observatory in blue, visible light observed by the Hubble Space Telescope in green, and infrared light from the Spitzer Space Telescope in red. This rare galaxy cluster has important implications for understanding how these megastructures formed and evolved early in the universe.
How Astronomers Time Travel
Let’s add another item to your travel bucket list: the early universe! You don’t need the type of time machine you see in sci-fi movies, and you don’t have to worry about getting trapped in the past. You don’t even need to leave the comfort of your home! All you need is a powerful space-based telescope.
But let’s start small and work our way up to the farthest reaches of space. We’ll explain how it all works along the way.
This animation illustrates how fast light travels between Earth and the Moon. The farther light has to travel, the more noticeable its speed limit becomes.
The speed of light is superfast, but it isn’t infinite. It travels at about 186,000 miles (300 million meters) per second. That means that it takes time for the light from any object to reach our eyes. The farther it is, the more time it takes.
You can see nearby things basically in real time because the light travel time isn’t long enough to make a difference. Even if an object is 100 miles (161 kilometers) away, it takes just 0.0005 seconds for light to travel that far. But on astronomical scales, the effects become noticeable.
This infographic shows how long it takes light to travel to different planets in our solar system.
Within our solar system, light’s speed limit means it can take a while to communicate back and forth between spacecraft and ground stations on Earth. We see the Moon, Sun, and planets as they were slightly in the past, but it's not usually far enough back to be scientifically interesting.
As we peer farther out into our galaxy, we use light-years to talk about distances. Smaller units like miles or kilometers would be too overwhelming and we’d lose a sense of their meaning. One light-year – the distance light travels in a year – is nearly 6 trillion miles (9.5 trillion kilometers). And that’s just a tiny baby step into the cosmos.
The Sun’s closest neighboring star, Proxima Centauri, is 4.2 light-years away. That means we see it as it was about four years ago. Betelgeuse, a more distant (and more volatile) stellar neighbor, is around 700 light-years away. Because of light’s lag time, astronomers don’t know for sure whether this supergiant star is still there! It may have already blasted itself apart in a supernova explosion – but it probably has another 10,000 years or more to go.
What looks much like craggy mountains on a moonlit evening is actually the edge of a nearby, young, star-forming region NGC 3324 in the Carina Nebula. Captured in infrared light by the Near-Infrared Camera (NIRCam) on NASA’s James Webb Space Telescope, this image reveals previously obscured areas of star birth.
The Carina Nebula clocks in at 7,500 light-years away, which means the light we receive from it today began its journey about 3,000 years before the pyramids of Giza in Egypt were built! Many new stars there have undoubtedly been born by now, but their light may not reach Earth for thousands of years.
An artist’s concept of our Milky Way galaxy, with rough locations for the Sun and Carina nebula marked.
If we zoom way out, you can see that 7,500 light-years away is still pretty much within our neighborhood. Let’s look further back in time…
This stunning image by the NASA/ESA Hubble Space Telescope features the spiral galaxy NGC 5643. Looking this good isn’t easy; 30 different exposures, for a total of nine hours of observation time, together with Hubble’s high resolution and clarity, were needed to produce an image of such exquisite detail and beauty.
Peering outside our Milky Way galaxy transports us much further into the past. The Andromeda galaxy, our nearest large galactic neighbor, is about 2.5 million light-years away. And that’s still pretty close, as far as the universe goes. The image above shows the spiral galaxy NGC 5643, which is about 60 million light-years away! That means we see it as it was about 60 million years ago.
As telescopes look deeper into the universe, they capture snapshots in time from different cosmic eras. Astronomers can stitch those snapshots together to unravel things like galaxy evolution. The closest ones are more mature; we see them nearly as they truly are in the present day because their light doesn’t have to travel as far to reach us. We can’t rewind those galaxies (or our own), but we can get clues about how they likely developed. Looking at galaxies that are farther and farther away means seeing these star cities in ever earlier stages of development.
The farthest galaxies we can see are both old and young. They’re billions of years old now, and the light we receive from them is ancient since it took so long to traverse the cosmos. But since their light was emitted when the galaxies were young, it gives us a view of their infancy.
This animation is an artist’s concept of the big bang, with representations of the early universe and its expansion.
Comparing how fast objects at different distances are moving away opened up the biggest mystery in modern astronomy: cosmic acceleration. The universe was already expanding as a result of the big bang, but astronomers expected it to slow down over time. Instead, it’s speeding up!
The universe’s expansion makes it tricky to talk about the distances of the farthest objects. We often use lookback time, which is the amount of time it took for an object’s light to reach us. That’s simpler than using a literal distance, because an object that was 10 billion light-years away when it emitted the light we received from it would actually be more than 16 billion light-years away right now, due to the expansion of space. We can even see objects that are presently over 30 billion light-years from Earth, even though the universe is only about 14 billion years old.
This James Webb Space Telescope image shines with the light from galaxies that are more than 13.4 billion years old, dating back to less than 400 million years after the big bang.
Our James Webb Space Telescope has helped us time travel back more than 13.4 billion years, to when the universe was less than 400 million years old. When our Nancy Grace Roman Space Telescope launches in a few years, astronomers will pair its vast view of space with Webb’s zooming capabilities to study the early universe in better ways than ever before. And don’t worry – these telescopes will make plenty of pit stops along the way at other exciting cosmic destinations across space and time.
Learn more about the exciting science Roman will investigate on X and Facebook.
Make sure to follow us on Tumblr for your regular dose of space!
3K notes
·
View notes
reminiscing ꩜ ln4
type: instagram/twitter au
Fans suffer days leading to love's holiday without their favorite couple.
lily said: hi! my first fic here, my first social media au ever, hope u enjoy :) will be a part 2 and 3..maybe more as well. whatever my heart desires and such
call her daddy podcast, 2/6/23
alex cooper and special guest: y/n l/n
y/n l/n: my friends keep trying to get me on dates, but i don't know, i'm just too much of a homebody right now. trying my best, but i'm rusty.
alex cooper: right, and i totally don't want to bring it up, if you don't want it out, but...
y/n l/n: no, it's totally fine. and yes, i'm single. it's one of those things i figured people will start to pick up on, it's kinda how life like this goes.
alex cooper: like a microscope on your relationship?
y/n l/n: exactly. made stuff super stressful, especially since we started dating when we were 19.
alex cooper: shit, 5 years is longer than i thought!
y/n l/n: we grew up together, had so many highlights and growing pains, and i don't want to get on your show and wallow or pout, that's really not what i feel. and i hope no one thinks anyone did anything wrong, it's just a growth thing. some people, as they grow, grow differently. and apart, i guess.
alex cooper: but you still have love for each other, i know that for sure.
y/n l/n: i'll never ever lose that love, i don't think.
Liked by pierregasly, arthur_leclerc, and 1,264,997 others
landonorris Quite a birthday today! Another year around the sun, another year of me kissing your face. Love you the most.
user1 yassss OUR girlfriend!
yourusername To the moon and back baby!!!!
yourusername Not pictured: his slobber on my cheek
landonorris You quite like my slobber, no?
oscarpiastri I surely don't
user2: you two really are growing up together :')
View more comments...
Liked by zendaya, kendalljenner, and 1,754,132 others
yourusername Sweet boy took me for a picnic, had too much wine hahaha. Thank you all for the birthday wishes, my heart is singing!!!! 23, woah am I close to getting old?
user1 SWEET BOY oh you people are sick
landonorris The most stunning girl, even napping
landonorris and yes you're old now
user2 CORNYYYY (i'm ready to end it all)
user3 "you're old now" and what are you??
emrata Wine's always a good idea
bellahadid happy birthday baby! come visit soon
user4 does that say lando on her necklace . i'm gonna snap soon
sza Loveeeee. U my favorite, Happy Solar Return!
View more comments...
Liked by alpinegoss, paddocktea, and 16,821 others
f1gossipcentral submission from a fan today in monaco:
i met lando today with a few others, he was so nice! we didn't want to ask flat out about y/n, he actually brought her up in passing when someone mentioned being from the same hometown as her, and he pointed it out himself. he didn't have the same energy we're used to when speaking about her, but it's obvious there was love in his voice, a lot of it. he's still got her friendship bracelet she made him last year on, but i think it's the type you'd have to cut to get off. regardless, i hope the best for him, and her too.
user1 you're telling me just the name of her hometown and he BLURTS about her?? AFTER being broken up??? yeah we're never seeing pearly gates atp
user2 is this what a broken home feels like?
user3 SHATTERED home. and yes.
user4 y/n lando please. come home the kids miss you
user5: single y/n...don't hate me but i would love a baddie era
user6: oh this is not a safe space for you.
View more comments...
1K notes
·
View notes