Hello Space Fans and welcome to another edition
of Space Fan News.
This week, observations from observatories
around the world and in space throw confusion
into our understanding of the rate of expansion
of the early universe; a simple chemistry
method could vastly enhance how scientists
search for signs of life on other planets;
and the ESA’s Gaia spacecraft turns its
eyes towards hunting asteroids.
First up, astronomers using the NASA/ESA Hubble
Space Telescope, the Keck Telescope, ESO’s
Very Large Telescope, the Subaru Telescope,
the Gemini Telescope, the Victor M. Blanco
Telescope, the Canada-France-Hawaii telescope
and the NASA Spitzer Space Telescope have
looked at gravitationally lensed galaxies
from the early universe and found that, well,
once again the early universe is confounding.
A group of astronomers using all these telescopes
and unapologetically calling themselves the
H0LiCOW collaboration, I’ll get to that
in a minute, arrive at an independent measurement
of the Hubble constant, and what they see
seems to say that the early universe was expanding
faster than we thought.
The Hubble constant, or H0, is very important
to astronomers because it describes the expansion
rate of the universe throughout it’s history.
It’s so important that measuring it accurately
was one of the main reasons the Hubble Space
Telescope was launched in the first place,
and over the decades, as our instruments have
gotten better and better, they’ve been able
to get that value down to within an amazing
3.8 percent.
This new measurement is completely independent
of — but in excellent agreement with — other
measurements of the Hubble constant in the
local Universe (that’s stuff relatively
nearby our Milky Way) that used Cepheid variable
stars and supernovae as points of reference.
But it is veering off estimates of H0 in the
early universe, these observations seem to
suggest that the early universe was expanding
faster than we thought.
And we we thought was brought to us by inferences
made from observations of the Cosmic Microwave
Background by ESA’s Planck space telescope.
Now astute viewers of Space Fan News may remember
back in SFN 182, I told you that a new survey
of Type 1a supernovae provided good evidence
that the rate of expansion in the universe
may be constant instead of accelerating.
So with these observations, you may be asking
yourself if astronomers know what the heck
is going on at all.
Now don’t be mad bro, but this is a good
thing.
I’ve been saying over and over again until
I’m blue in the face that what we’re experiencing
with all this apparently conflicting information
is a very good thing.
Astronomers have way too many models describing
how they think the universe works, so many
that they can’t all be right.
But what we have needed for a long time, and
are now finally getting because of all these
great detectors, observatories and spacecraft
at our disposal - is direct observations.
Data.
These observations help us throw away the
models that don’t seem to do a good job
of describing the universe in favor of those
that do, something we’ve needed ever since
humanity first looked up at the sky and thought
all those points of light up there were little
fires.
So what these H0LICOW astronomers did was
look at massive galaxies between Earth and
very distant quasars — which have incredibly
bright galaxy cores.
The light from the more distant quasars is
bent around the huge masses of the galaxies
as a result of strong gravitational lensing].
This creates multiple images of the background
quasar, some smeared into extended arcs.
Because galaxies do not create perfectly spherical
distortions in the fabric of space and the
lensing galaxies and quasars are not perfectly
aligned, the light from the different images
of the background quasar follows paths which
have slightly different lengths.
And what you may not know about quasars is
that they flicker because they are supermassive
black holes feeding off of infalling material
and since the brightness of quasars changes
over time, astronomers can see the different
images flicker at different times, the delays
between them depending on the lengths of the
paths the light has taken.
These delays - and here’s the kicker - are
directly related to the value of the Hubble
constant.
What’s great about this measurement is that
it is independent of all other means of measuring
the expansion rate of the universe and is
relatively simple.
It depends only on the geometry of the light
path as it travels to us.
No CMB inferences like those made by Planck,
no Cepheid variable measurement, no Type 1a
Supernovae light curves.
So, these measurements agreed with local models
of the universe but disagreed with the more
distant universe.
And because we now have at our disposal, different
ways to measure the Hubble constant with such
high precision, astronomers are saying that
these discrepancies may possibly point towards
new physics beyond our current knowledge of
the Universe.
In other words, maybe all the models have
to be thrown out.
So back to H0LiCOW.
It stands for H0 Lenses in COSMOGRAIL’s
Wellspring, and don’t worry you’ll never
remember that - I’ve already forgotten it.
And since the best acronyms have more acronyms
embedded in them, COSMOGRAIL stands for Cosmological
Monitoring of Gravitational Lenses.
Yeah, I won’t be mentioning that one ever
again.
So, if you want to learn more about what these
guys did and how they did it, they made a
video about it and you should go check it
out.
I put a link to it in the description box
below.
Next researchers from JPL in Pasadena California,
have developed a new, simple and highly accurate
test for life on other worlds.
The test uses a liquid-based technique known
as capillary electrophoresis to separate a
mixture of organic molecules into its components.
It was designed specifically to look for amino
acids which are the structural building blocks
of all life on Earth.
This method is 10,000 times more sensitive
than current methods being used by spacecraft
like NASA's Mars Curiosity rover.
The researchers used the technique to analyze
amino acids present in the salt-rich waters
of Mono Lake in California.
The lake's exceptionally high alkaline content
makes it a challenging habitat for life, and
an excellent stand-in for salty waters believed
to be on Mars, or the ocean worlds of Saturn's
moon Enceladus and Jupiter's moon Europa.
The researchers were able to simultaneously
analyze 17 different amino acids, which they
are calling "the Signature 17 standard."
These amino acids were chosen for study because
they are the most commonly found on Earth
or elsewhere.
Using this method, they were able to tell
the difference between amino acids that come
from non-living sources like meteorites versus
amino acids that come from living organisms.
Another thing about amino acids is this thing
called "chirality."
Chiral molecules such as amino acids come
in two forms that are mirror images of one
another.
Although amino acids from non-living sources
contain approximately equal amounts of the
"left" and "right"-handed forms, amino acids
from living organisms on Earth are almost
exclusively the "left-handed" form.
It 
is expected that amino acid life elsewhere
would also need to "choose" one of the two
forms in order to create the structures of
life.
For this reason, chirality of amino acids
is considered one of the most powerful signatures
of life.
I think capillary electrophoresis may become
an option on future model years of Mars Rovers,
we’ll have to wait and see what the dealers
say.
Finally a follow up on a story I did back
in SFN 178 where I told you about the Gaia
mission.
Gaia is run by the European Space Agency and
is designed to measure the positions of stars
in our galaxy, and do it more accurately than
ever before.
It is mapping about a billion stars, roughly
1% of the the stars in our Galaxy
Well, in addition to mapping stars, Gaia is
now turning its powerful mapping capabilities
towards looking for asteroids, something I
have long argued we have been needed to do
a whole lot more of.
I dunno about you but I don’t want to be
hit by one of those suckers so the more we
know, the better as far as I’m concerned.
Anyway, ESA announced this week that in addition
to mapping stars, for the first time, Gaia
is not only providing information crucial
to understanding known asteroids, it has also
started to look for new ones, previously unknown
to astronomers.
Since it began scientific operations in 2014,
Gaia has played an important role in understanding
Solar System objects.
While this was never the main goal of Gaia,
it is a valuable side effect of its work.
Gaia's observations of known asteroids have
already provided data used to characterise
the orbits and physical properties of asteroids
more precisely than ever before.
All of the asteroids studied up until now
were already known to the astronomy community.
These asteroids were seen in Gaia data as
spots that were present in one image and gone
in one taken a short time later, suggesting
they were in fact objects moving against the
more distant stars.
Once identified, moving objects found in the
Gaia data are matched against known asteroid
orbits to tell us which asteroid they are
looking at.
Now, for the first time, they are finding
moving objects that can't be matched to any
catalogued star or asteroid.
They identify these moving objects automatically,
using software.
Gone are the days of the lonely astronomer
sitting at a blink comparator looking for
motion, the star fields from Gaia are way
too crowded for that to be practical.
Once it finds a candidate asteroid, the software
alerts astronomers for a closer look.
Using this software, imaginatively named Initial
Data Processing (IDT) software, Gaia has now
found an asteroid barely observed before.
The asteroid in question, nicknamed Gaia-606,
was found in October 2016 when Gaia data showed
a faint, moving source.
Astronomers immediately got to work and were
able to predict the new asteroid's position
as seen from the ground over a period of a
few days.
Gaia-606 was found in the main asteroid belt,
which is not surprising given how many asteroids
are there.
However, Gaia also provides data from swathes
of the sky not extensively observed by existing
ground-based surveys giving it the potential
to find asteroids in areas where others would
not look.
So I for one, am glad they’re using Gaia
for this.
I’m sure we’ll get more discoveries of
asteroids from Gaia in the coming months
as it searches the sky while mapping stars.
This is just one more example of how imaginative
scientists can be when using science spacecraft
to get the every possible drop of science
from their instruments.
Well done guys and I’ll keep you posted.
Well, that’s it for this week Space Fans,
thanks so much to all SFN Patreon Patrons,
look for a contest coming up in February for
you guys.
Thanks to all of you for watching and as always,
Keep Looking Up!
