With modern computer graphics, it’s sometimes hard to know which is an actual photograph
of space, and what’s an illustration or a 3D rendering.
Some really fascinating discoveries don’t have a pretty picture to go along with them,
so illustrations are created to help us understand.
Astronomers are pretty lucky.
Their scientific work happens to produce some of the most beautiful and iconic images in
all of science.
Here’s the famous Pillars of Creation, taken by the Hubble Space Telescope, or the Helix
Nebula.
Here are the rings of Saturn, captured by Cassini.
Amazing.
Beautiful to look at, but more importantly, they have a scientific purpose for researchers.
Now let’s take a look at some other images to go along with recent discoveries in space
and astronomy.
First, here are the 7 Earth-sized worlds discovered in the TRAPPIST-1 system.
Of course, that’s a computer illustration.
Here’s the actual data.
And remember the recent collision between neutron stars that generated a kilonova explosion,
where both gravitational waves and electromagnetic radiation were detected here on Earth?
Here’s the chirp LIGO heard in gravitational waves.
Here’s the view in visible light.
Need help finding it?
It’s right…
there.
If you want to explain what’s going on to the public, you’ll need to provide images
and illustrations.
In some cases you can use the raw photographs themselves, other times you need to do some
processing on the images, and sometimes you have to create illustrations based on the
story the data is telling.
Which one is which, and how can you know?
The reality is that almost every astronomical image you’ve ever seen has been processed
to some extent.
Actually, you could say the same thing for almost every picture ever, but I digress.
But let me give you some examples.
Unlike your phone camera, which can capture images in full color, almost all astronomical
telescopes are equipped with a black-and-white CCD.
That’s great for image quality, but less, uh, pretty.
Astronomers then use filters, which block the light from large parts of the spectrum,
isolating exactly what they want to look at.
If you want to see certain kinds activity on the Sun, for example, or the light from
emission nebulae, you use a hydrogen alpha filter.
This only lets photons of light in that match 656.28 nanometers.
Here’s what the Sun looks like with regular visible light, and here’s what it looks
like with the hydrogen alpha filter.
You can see how the hydrogen alpha version lets you see coronal loops and other activities
on the Sun.
NASA’s Solar Dynamic Observatory has many other filters it can use, at different wavelengths
from visible to ultraviolet.
This picture, for example, shows the Sun using a filter for 211 angstroms, which corresponds
to the emissions of Iron-14 at 2 million kelvin.
They color these images purple it’s easy to know at a glance which filter you’re
looking at.
The Hubble Space Telescope is equipped with 80 different filters that astronomers can
choose from when they book time on the telescope.
A certain number of hours with this filter, and then a certain number of hours with that
filter.
Then all the data is downloaded in a special image format called FITS, which stands for
the Flexible Image Transport System.
It’s useful for astronomers because it contains additional metadata about the image that astronomers
need.
So, when you see a photograph of some object taken by the Hubble Space Telescope, you’re
seeing the scientific data which has then merged together in Photoshop in an artistic
manner.
The scientific data is real, but an artist made an arbitrary decision to assign red to
the hydrogen alpha filter and then blue to oxygen and green to sodium.
They should have just as easily switched those colors around, or used different colors entirely.
And chances are, a scientist was never involved in this process.
They’re happy with the raw black-and-white FITS files.
Here’s a recent picture of a supermassive black hole in the galaxy SDSS J1354+1327.
This image is actually made up of images captured by separate space telescopes.
Red comes from one of Hubble’s infrared filters.
Green and blue come from ultraviolet filters, and pink comes from the Chandra X-Ray Observatory,
to show the excited regions around a black hole.
Unless you have some kind of superpowers, your eyes can’t see infrared, ultraviolet
or X-rays.
Sometimes there’s raw data, but an artist or illustrator will use that to create an
artist’s conception of what that is.
Almost all the images of black holes you’ve ever seen were created by artists.
For example, when you see this kind of image showing the distortion of a black hole against
background stars, that’s an illustration.
Someone with a knowledge of physics has simulated the gravity distorting effects of a black
hole event horizon.
It’s scientifically accurate, but it’s an illustration.
Here’s an actual image of the region around the center of the Milky Way, which contains
the our supermassive black hole.
You can see this bright region where stars are compacted incredibly close together and
the light echoes from radiation blasted out into space.
That’s in X-rays from the Chandra Observatory again.
This one’s pretty tricky though, it looks like a photograph but it’s actually an illustration
based on scientific data captured by the Herschel Space Telescope.
Here’s what it really looks like.
In the next couple of months, we’re going to see the first images from the Event Horizon
Telescope, which used a worldwide network of radio telescopes to take the first ever
image of the event horizon around the supermassive black hole at the heart of the Milky Way.
It’s going to be scientifically fascinating, but it’ll probably just look like a blob.
So, prepare yourself emotionally for that.
In a second I’m going to show you some amazing examples of how skilled artists can work with
this scientific data to create amazing images, but first I’d like to thank:
Sre Harsha Remella Josh Susser
Ken Hurst Larry Beckham
Neuterdude Dylan O'Donnell
Rob Jones Matthew Stewart
Android Virgil 21
And the rest of our 807 patrons for their generous support.
If you love what we’re doing and want to get in on the action, head over to patreon.com/universetoday.
Some of my favorite space images are a blend between scientific data and artistic ability.
And one of the greatest examples of this is the torrent of data coming back from NASA’s
Juno spacecraft currently at Jupiter.
When NASA was originally building the spacecraft, they didn’t feel it was necessary to include
a visible light camera.
Which, I know, sounds crazy.
But wise people encouraged them to include a visible instrument: JunoCam, to allow the
public to see what’s happening at Jupiter, and to get involved in reviewing and processing
images from the raw data.
All the data from JunoCam is uploaded directly to the internet, and citizen scientists and
artists have access to this data to create their own images however they like.
First, I’d like to show you what the raw data looks like, sent back from JunoCam.
It has a CCD sensor with a resolution of 1600 x 1200 pixels with a 58 degree field of view.
It has 4 different filters that it takes pictures with: red, green, blue and methane.
Citizen scientists can then take these raw images, bring them into Photoshop and mix
and match to create photographs like this or this.
This is the work of one of my favorite citizen scientists, Kevin Gill.
And I want to show you another series of images he’s working on.
This is the Western Rim of the Palikir Crater on Mars.
But this isn’t real, it’s actually a 3D rendering of the surface of Mars made by Kevin
to show you what it would look like to be standing on Mars.
But Kevin based this rendering on data from NASA’s Mars Reconnaissance Orbiter.
There’s a dark side to internet imagery: fakes and misrepresentations.
When anyone posts an image to the internet, I think it’s really important to provide
credits and sources, so people can follow back to find out where an image came from.
But after big events, like eclipses and meteors, we see a lot of fakes.
For example, check out this amazing video of a huge meteor burning up in the atmosphere.
I see this posted to Twitter every time there’s a big fireball sighting.
Except it’s not a meteor, it’s a video of the European Space Agency’s Jules Verne
cargo ship burning up in the atmosphere a few years ago.
Sometimes an artist creates an image and then other people repost it without permission
putting it out of context, and sometimes people post deliberately fake images for trolling
or, I don’t know… reasons?
One of my favorite Twitter feeds is Fake Astropix, which debunks space pictures and videos on
a regular basis.
You’ll learn so much from this account.
I absolutely love looking at pictures of space.
But when I do, I take second to make sure I understand what I’m looking at.
Whether it’s a true color image of space, a composite image based on real scientific
data, or an artist’s illustration.
Each of these has their place, whether it’s to show the public what’s actually being
seen out there or to help them understand the significance of the discoveries.
It’s this partnership between space agencies and the public that I’m so excited about.
Every time there’s a mission, we see these amazing pictures coming back.
Beautiful to look at, but based on real scientific data.
If you have any skills in this area, and want to get involved, I’ll put some links in
the show notes so you can find out more.
Ask for Comments: How do you feel about the role of photographs
and illustrations for helping to communicate the results of astronomy and space exploration
to the public?
Let me know your thoughts in the comments.
Once a week I gather up all my space news into a single email newsletter and send it
out.
It’s got pictures, brief highlights about the story, and links so you can find out more.
Go to universetoday.com/newsletter to sign up.
And finally, here’s a playlist.