Hello Space Fans and welcome to another edition of Space Fan News.
In this episode, NASA's OSIRIS-Rex spacecraft flies by Earth to get a gravity-assist boost
to get the asteroid Bennu; The Venerable Very Large Array Radio Telescope in New Mexico
gets an upgrade and begins a new era of observations; The New Horizons Spacecraft files its new
flight plan after passing by Pluto; and Astronomers think they know how primordial black holes
were formed.
Australian Space Fans, it's a good thing we always keep looking up here at SFN because
you guys are going to see something special tonight (or rather tomorrow morning) at midnight.
The NASA Spacecraft OSIRIS-Rex will pass over parts of Australia as flies some 17,000 kilometers
(11,000 miles) overhead while it gets a gravity assist from the Earth to help speed it on
its way to its destination: the asteroid known as Bennu.
Unfortunately, you can't see it with your naked eye, it's too dim for that (after
all, it's a pretty small spacecraft), but if you have a small telescope, or a big lens
on the back of an SLR camera, then experts are saying you might be able to get a glimpse.
The apparent pathway of the spacecraft over Australian skies will take about an hour,
beginning over Rockhampton in Queensland at 00.22am local time on September 23 and exiting
over Adelaide at 00.53am local time.
So if I were in Australia, and I had a little telescope, I'd be out there giving this
a try.
If any Australian Space Fans are going to try and see it, please leave us all a comment
in this video letting us know how it went so we can all live vicariously through you
during this event.
I've reported on OSIRIS-REx many times, but to remind you, this mission is the first
ever to travel to an asteroid, try to get a piece of it, then bring it back to Earth.
Bennu was selected from over 500,000 known asteroids by the OSIRIS-REx selection committee.
The primary reason for its selection was it had a close proximity to Earth, and the relatively
low velocities required to reach it from Earth orbit.
It is also an asteroid in an orbit with low eccentricity, low inclination, and an orbital
radius of 0.8–1.6 AU.
It wasn't flying around in some bizarre, hard-to-get-to orbit.
So, basically it was close and relatively easy to get to.
What's interesting about Bennu, at least to me, is that this asteroid is classified
as a potential Earth impactor that has a 1-in-2,700 chance of hitting the Earth in the late 22nd
century.
So this asteroid is well worth keeping an eye on.
For those in the 22nd century.
Shortly after tonight's flyby, OSIRIS-REx is gonna do something kinda cool, it will
turn around and look back at Earth and take images and spectra of our home planet.
They are doing this to ensure that the instruments are ready for arrival at Bennu later next
year in 2018.
But it's also gonna take some pretty cool images of Earth too, and that's another
good reason.
Next The Venerable Very Large Array Radio Telescope located in Socorro, New Mexico has
been around a while, you guys probably remember it from the movie Contact, but it has been
around since the 1970's taking awesome, albeit somewhat fuzzy radio images of objects
in the sky.
The VLA consists of a group of 28 radio telescopes, each with a 25 meter dish and the entire complex
spans a diameter of about 23 miles.
Each dish moves on a rail that allows the configuration of the array to be altered for
a variety of scientific needs and also let's them bring each telescope in for servicing
or upgrades.
Which bring me to this week's story.
The VLA has just completed a huge upgrade from its 1970's technology that brings it
into the 21st century.
The upgrade was completed in 2012 and is called the New VLA Sky Survey (VLASS).
And this year marks the beginning of a new era for VLASS.
Over the next 7 years, this iconic array of giant dish antennas in the high New Mexico
desert will make three complete scans of the sky that is visible from its latitude and
that includes about 80 percent of the entire sky.
Here's an example of the new capabilities of VLASS.
This is a radio-emitting object as seen with the old VLA Sky Survey, the FIRST Survey which
had higher resolution, and the newly improved VLASS.
The VLASS image, as you can easily see, allows astronomers to positively identify the image
as jets of material propelled outward from the center of a galaxy that also is seen in
the visible-light Sloan Digital Sky Survey.
Astronomers expect the VLASS to discover powerful cosmic explosions, such as supernovae, gamma
ray bursts, and the collisions of neutron stars, that are obscured from visible-light
telescopes by thick clouds of dust, or that otherwise have eluded detection.
The VLA's ability to see through dust will make the survey a tool for finding a variety
of structures within our own Milky Way that also are obscured by dust.
I'll keep you posted.
Okay, next by now you've all heard that the New Horizons spacecraft has passed Pluto,
taken some amazing pictures and then zoomed passed heading for the outer reaches of the
solar system.
With some help from Hubble to pick out a good spot to head to, mission planners decided
on Kuiper Belt object 2014 MU69,
Early in September, mission planners announced a few more details of the flyby.
New Horizons is expected to reach MU69 on New Years Day 2019 and they are aiming to
come three times closer to MU69 than when it flew past Pluto in 2015.
If all goes as planned, New Horizons will come to within just 2,175 miles (3,500 kilometers)
of MU69 at closest approach, peering down on it from celestial north.
The alternate plan, which will be employed in certain contingency situations such as
the discovery of debris near MU69, would take New Horizons within 6,000 miles (10,000 kilometers)
which is still closer than it go to Pluto when it flew over at 7,800-miles (12,500-kilometers).
I wonder if the New Year's Day thing was a coincidence or if they somehow planned it
that way.
I mean, Juno go to Jupiter on July 4th (ok, July 5th).
I'm just trying to find a conspiracy here folks.
We know NASA is responsible for a lot of them.
Finally, some physicists from UCLA have proposed new theories for how the universe's first
black holes might have formed and the role they might play in the production of heavy
elements such as gold, platinum and uranium.
The question of how the very first black holes in the universe formed has bugged astronomers
for a long time.
Did they form seconds after the big bang?
Or did they form millions of years later during the deaths of the earliest stars?
No one knew.
And it was bothersome.
The guys from UCLA have come up with a compellingly simple new theory that suggests black holes
could have formed very shortly after the Big Bang, long before stars began to shine.
Astronomers have previously suggested that these so-called primordial black holes could
account for all or some of the universe's mysterious dark matter and that they might
have seeded the formation of supermassive black holes that exist at the centers of galaxies.
This new theory proposes that primordial black holes might help create many of the heavier
elements found in nature.
They started by saying, "Hey, let's say there is a uniform field of energy pervading
the universe shortly after the Big Bang."
Scientists expect that such fields existed in the distant past.
After the universe rapidly expanded, this energy field would have separated into clumps.
Gravity would cause these clumps to attract one another and merge together.
The UCLA researchers proposed that some small fraction of these growing clumps could have
become dense enough to become black holes.
If this is what happened, then we should see these primordial black holes in observations
of gravitational microlensing where the light from a distant star causes some funky light
curves that would show up as the black hole passed in between the telescope and the star.
And as it happens, earlier this year, U.S. and Japanese astronomers published a paper
on their discovery of one star in a nearby galaxy that brightened and dimmed precisely
as if a primordial black hole was passing in front of it.
So what does all this have to do with Gold, platinum and Uranium?
What I didn't know is that it's long been a puzzle to astronomers where these elements
in the universe came from.
Think about it, stellar fusion stops at Iron, with an atomic number of 26.
Gold, Platinum and Uranium are much higher up on the periodic table, so where did they
come from?
Well the UCLA guys are suggesting that if one of these primordial black holes collides
with a neutron star, which are the city-sized, spinning remnants of a star that remains after
some supernova explosions, and sinks into its depths of the neutron star.
This is so cool.
When that happens, the primordial black hole consumes the neutron star from the inside,
a process that takes about 10,000 years.
As the neutron star shrinks, it spins even faster, eventually causing small fragments
to detach and fly off.
Those fragments of neutron-rich material may be the sites in which neutrons fuse into heavier
and heavier elements.
Unfortunately, the probability of a neutron star capturing a black hole is rather low,
and this is consistent with observations of only some dwarf galaxies being enriched in
heavy elements.
Still, the theory that primordial black holes collide with neutron stars to create heavy
elements would explain the observed lack of neutron stars in the center of our Milky Way
galaxy, which has been another long-standing mystery in astrophysics.
Bring on those microlensing observations!
Well, that is it for this episode Space Fans.
SFN is made possible in part by Deep Astronomy Patreon Patrons who get access to new material
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Thanks so much for supporting.
Thanks to all of you for watching and as always, Keep Looking Up!
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