Hey everybody and welcome to another Deep
Astronomy vlog post, my name is Tony Darnell
and I run Deep Astronomy dot space.
A place where we’ve been looking up since
2006.
Today, I want to talk about our night sky
and whether or not the upcoming swarm of satellites
planned for launch into low Earth orbit is
going to ruin our night skies.
Now if you haven’t heard this yet, in late
May of this year, SpaceX launched a group
of sixty satellites into low Earth orbit with
the goal of providing global internet coverage,
something I support, but it comes with a lot
of problems.
These satellites that were launched this year
was the first of what could be up to a total
of 12,000 satellites and so far the FCC has
approved almost 1,600 to be launched and operated.
From the very first video I ever made on YouTube
way back in 2006, I’ve been saying this:
“When you look up at the night sky on a
clear, dark night, you can see about 3,000
stars.”
That’s it.
Three thousand stars with your naked eye on
a night with no clouds and from a place that
doesn’t have light pollution, which is a
different but related to the problem we’re
talking about today.
Alex Parker, a planetary astronomer on Twitter,
puts that estimate higher at 9000 stars, but
I think that’s way optimistic.
Even well-adapted for darkness, I don’t
think our eyes can see that many.
So we can split the difference and I’ll
go as high as 5000 stars.
So SpaceX wants to put 12,000 bright, shiny,
reflective satellites 550 km over our heads.
They are very bright and 12,000 is a lot and
each one would be bright enough to be seen
by the naked eye.
And they aren’t the only company that wants
to do this.
Amazon has Project Kuiper which is currently
in the design stage that will have 3,236 satellites
in low Earth orbit — including 784 satellites
at an altitude of 590km; 1,296 satellites
at a height of 610km; and 1,156 satellites
in 630km orbits.
So from just SpaceX and Amazon 15,236 satellites
would be put into Earth orbit, and there are
more companies that want to do something similar,
Google has been trying for a while with Project
Loon, which tries to use balloons floating
in the stratosphere to provide internet and
Facebook has project Athena, which so far
is just a cubesat millimeter-wave experiment
that has also been granted by the FCC to operate
but one can imagine that this project will
also grow to hundreds if not thousands of
satellites to be able to achieve global coverage.
And all of this folks is on top of the 20,000
or so satellites that are already there.
If you haven’t seen this, go check it out:
this is stuffin dot space.
And this website shows you in real time where
all the satellites in orbit are right now
above the Earth.
It’s stupendous what how much stuff we have
up there.
If you haven’t yet, you should play around
with this interface, it shows you where the
GPS satellites are, rocket bodies left up
there by SpaceX all kinds of stuff.
I didn’t see the 60 starlink satellites
yet but I’ve only been playing with this
for a short time.
You should definitely go check it out though.
I’m not going to go into the other issues
with so many satellites in orbit overhead
- not the least of which is the Kessler syndrome
where the density of satellites becomes high
enough that collisions between them start
to cascade a create a real mess - I’ll take
that one on in a future video, for now, I
want to focus on how all of these satellites
will affect our night sky, namely using telescopes
on the ground to learn about the universe.
Ok so after SpaceX released the first batch
of sixty satellites, Lowell observatory in
Arizona tried to image the galaxy group NGC
5353/4 on the night of May 25, 2019 and saw
this mess superimposed on the field.
Those hugely distracting diagonal lines are
more than 25 of the 60 satellites that passed
through the field of view of the telescope
during the exposure.
Even allowing for the fact that this was taken
shortly after the deployment where they were
all bunched up, it has been estimated by Alex
Parker that if all 12,000 get launched about
500 of them will be above the horizon and
directly illuminated by the Sun, creating
a megaconstellation of satellites with each
one having a 2nd or 3rd magnitude brightness.
It’s also important to note that the satellites
in this image had not reached their final
altitude when this was taken, so we’ll need
to look again, but this is quite alarming.
In the Twitter thread I have linked to below,
exoplanet astronomer Hugh Osborn calculated
that at 550 km, any one observer can see 3.6%
of the 12,000 satellites at any one time,
which is 430 satellites, and during the high-latitude
summer nights, a large fraction will be illuminated.
The exact number will depend a lot on the
specifics once they’re all up there but
Cees Bassa, another astronomer on Twitter
calculated that of the 1,600 Starlink satellites
already approved to fly, 84 would be above
the horizon with 15 that would be sunlit and
visible above 30 degrees latitude.
At 52 degrees latitude and above, they’d
be lit throughout the night from May to mid-August.
Now you may think that all of this is just
silly, that astronomers are getting their
panties in a bunch over nothing and that the
benefits of global high-speed internet availability
far outweigh the downside of astronomers being
able to actually observe the universe, and
you may have a point, I don’t know.
I do know that I’m biased towards being
able to see the stars, but then I have a pretty
good internet connection so that’s easy
for me to say I guess.
There has been a lot of pushback from SpaceX
fans, especially on Twitter, telling astronomers
to get over it with this guy Luis leading
the charge to defend SpaceX.
But I want to be clear on something: No one,
not even astronomers, are trying to make the
case that these projects shouldn’t be done.
Instead we should think carefully about the
effects swarms of satellites that will easily
double what’s already up there will have
in all areas of our lives.
The concern of astronomers over this issue
is growing.
Both the American Astronomical Society and
the International Dark Sky Association have
both come out with statements reflecting their
concerns and expressing the desire for companies
working on global satellite swarms like this
to work with astronomers.
Remember, we are in the process of building
some of the largest ground-based telescopes
ever seen, at a cost of billions of dollars:
there’s the Extremely Large Telescope being
built in Chile, the Thirty Meter Telescope
is starting construction now on Mauna Kea
in Hawaii, the Large Synoptic Survey Telescope
is getting ready to start taking data hopefully
sometime next year and many more are in the
pipeline and design stages.
And all of them depend on collecting photons
that push their design limits.
To see things like planets around other stars,
the first stars ever to shine in the universe,
the first galaxies ever to form anywhere,
and to look for faint technosignatures of
any civilizations that might be out there,
we have to have as clear a view as possible
and looking through this is not helpful.
Not to mention the telescopes that we amateur
astronomers have in our backyards.
Imagine you’ve spent an evening getting
a long-exposure shot of the Ring Nebula and
while it was collecting light, several satellites
streaked through the frame.
Can these artifacts be removed? of course
they can, but it comes at the cost of data
accuracy, the error bars of measurements go
up whenever you heavily process an image and
when you’re already at the limits of the
optical system, this can have a real detrimental
effect on the quality of the data.
You can’t just use the Healing brush in
Photoshop to take the satellite trails out,
the data would be all but wiped out as well.
But that’s not all, remember when I used
to always say the future of astronomy is in
the infrared?
Well that was 10 years ago and that future
is here, IR telescopes are currently transforming
our understanding of the universe.
The future of astronomy now lies in the radio
with telescopes like ALMA and the Square kilometer
array.
The star link satellites and others like it
will be transmitting in a frequency band very
close to one commonly used for astronomy and
will likely cause interference.
This might actually be more of an issue than
the satellite trails in an optical image,
depending on the shielding they put into them.
And yes, I hear you, making space more profitable
is a great way towards expanding to the stars
and I absolutely support companies trying
to do just that.
But I don’t support an everything goes approach
either.
As the IDSA rightly points out, the night
sky is a resource and treasure for all of
us to enjoy and in the same way that companies
should not be allowed to start mining the
Grand Canyon, or ripping apart the cloud forests
of Costa Rica to make room for industry, so
too careful thought should be given to the
night sky.
Can there be a balance between the competing
interests of companies like SpaceX, Amazon
and Facebook who want to bring internet connectivity
to everyone, although I don’t think they
want to do it for purely altruistic reasons,
with the needs of the rest of us - many who
have already lost our dark skies to cities
- who need an unobstructed view of the heavens
in our efforts to learn more about our place
in the universe?
The solution, whatever it is, won’t be easy
to come by, but we absolutely have to start
talking about it now.
At the very least, I think we have to stop
stuff like this: remember Humanity Star?
It was a bright disco ball that went up last
year for no other reason than to be bright
and reflective.
That was completely unnecessary and let’s
all just agree not to do that again, shall
we?
There’s also the company that wants to put
billboards in space, should we allow that?
At some point, astronomical research from
the ground will become all but impossible
if these things are left unchecked, so talking
about it now is key.
Well that’s it for now Space Fans, thanks
to Deep Astronomy Patreon Patrons who keep
these videos coming, and thanks to all of
you for watching and as always, Keep Looking
Up!
Even if it is through a veil of satellites….
