- 4334
- ASTEROID -
sample returned? NASA's OSIRIS
REx asteroid sample the most expensive material on Earth? The mission cost $1.16 billion for just under
9 ounces of asteroid dust. But it's hardly the most expensive material in
science.
------------------------------------ Asteroid Bennu
------------------------- 4334
- ASTEROID -
sample returned
-
- After a journey of seven years and nearly 4
billion miles, NASA's “OSIRIS-REx” spacecraft landed gently in the Utah desert
on the morning of September 24, 2023, with a precious payload. The spacecraft
brought back a sample from the asteroid Bennu.
-
- Roughly half a pound of material collected
from the 85 million-ton asteroid will
help scientists learn about the formation of the solar system, including
whether asteroids like Bennu include the chemical ingredients for life.
-
- NASA's mission was budgeted at $800 million
and will end up costing around $1.16 billion for just under 9 ounces of sample
(255 g). But is this the most expensive material known? Not even close.
-
- A handful of asteroid works out to $132
million per ounce, or $4.7 million per gram. That's about 70,000 times the
price of gold, which has been in the range of $1,800 to $2,000 per ounce ($60
to $70 per gram).
-
- The first extraterrestrial material returned
to Earth came from the Apollo program. Between 1969 and 1972, six Apollo
missions brought back 842 pounds of
lunar samples.
-
- The total price tag for the Apollo program,
adjusted for inflation, was $257 billion. These Moon rocks were a relative
bargain at $19 million per ounce ($674 thousand per gram).
-
- NASA is planning to bring samples back from
Mars in the early 2030s to see if any contain traces of ancient life. The Mars
Sample Return mission aims to return 30 sample tubes with a total weight of a
pound (450 g). The Perseverance rover has already cached 10 of these samples.
-
- However, costs have grown because the
mission is complex, involving multiple robots and spacecraft. Bringing back the
samples could run $11 billion, putting their cost at $690 million per ounce
($24 million per gram), five times the unit cost of the Bennu samples.
-
- Some space rocks cost nothing. Almost 50
tons of free samples from the solar system rain down on the Earth every day.
Most burn up in the atmosphere, but if they reach the ground they're called
meteorites, and most of those come from asteroids.
-
- Most meteorites are stony, called
chondrites, and they can be bought online for as little as $15 per ounce (50
cents per gram). Chondrites differ from normal rocks in containing round grains
called chondrules that formed as molten droplets in space at the birth of the
solar system 4.5 billion years ago.
-
- Iron meteorites are distinguished by a dark
crust, caused by melting of the surface as they come through the atmosphere,
and an internal pattern of long metallic crystals.
-
- They cost $50 per ounce ($1.77 per gram)
or even higher. Pallasites are stony-iron meteorites laced with the mineral
olivine. When cut and polished, they have a translucent yellow-green color and
can cost over $1,000 per ounce ($35 per gram).
-
- More than a few meteorites have reached us
from the Moon and Mars. Close to 600 have been recognized as coming from the
Moon, and the largest, weighing 4 pounds (1.8 kg), sold for a price that works
out to be about $4,700 per ounce ($166 per gram).
-
- About 175 meteorites are identified as
having come from Mars. Buying one would cost about $11,000 per ounce ($388 per
gram).
-
- Researchers can figure out where meteorites
come from by using their landing trajectories to project their paths back to
the asteroid belt or comparing their composition with different classes of
asteroids. Experts can tell where Moon and Mars rocks come from by their
geology and mineralogy.
-
- The limitation of these "free"
samples is that there is no way to know where on the Moon or Mars they came
from, which limits their scientific usefulness. Also, they start to get
contaminated as soon as they land on Earth, so it's hard to tell if any
microbes within them are extraterrestrial.
-
- Some elements and minerals are expensive
because they’re scarce. Simple elements in the periodic table have low prices.
Per ounce, carbon costs one-third of a cent, iron costs 1 cent, aluminum costs
56 cents, and even mercury is less than a dollar (per 100 grams, carbon costs
$2.40, iron costs less than a cent and aluminum costs 19 cents). Silver is $14
per ounce (50 cents per gram), and gold, $1,900 per ounce ($67 per gram).
-
- Seven radioactive elements are extremely
rare in nature and so difficult to create in the lab that they eclipse the
price of NASA's Mars Sample Return. Polonium-209, the most expensive of these,
costs $1.4 trillion per ounce ($49 billion per gram).
-
- Gemstones can be expensive, too.
High-quality emeralds are 10 times the price of gold, and white diamonds are
100 times the price of gold.
High-quality white diamonds can cost millions of dollars.
-
- Some diamonds have a boron impurity that
gives them a vivid blue hue. They're found in only a handful of mines
worldwide, and at $550 million per ounce ($19 million per gram) they rival the
cost of the upcoming Mars samples, an ounce is 142 carats, but very few gems
are that large.
-
- The most expensive synthetic material is a
tiny spherical "cage" of carbon with a nitrogen atom trapped inside.
The atom inside the cage is extremely stable, so can be used for timekeeping.
“Endohedral fullerenes” are made of carbon material that may be used to create
extremely accurate atomic clocks. They can cost $4 billion per ounce ($141
million per gram).
-
- Antimatter occurs in nature, but it's
exceptionally rare because any time an antiparticle is created it quickly
annihilates with a particle and produces radiation.
-
- The particle accelerator at CERN can
produces 10 million antiprotons per minute. That sounds like a lot, but at that
rate it would take billions of years and cost a billion billion (10^18) dollars
to generate an ounce (3.5 x 10^16 dollars per gram)
-
- Last year Earth had more
than 100 close encounters with large asteroids. What are the odds of a direct
hit in the near future?
-
- Asteroids are chunks of rock left over from
the formation of our Solar System. Approximately half a billion asteroids with
sizes greater than four metres in diameter orbit the Sun, traveling through our
Solar System at speeds up to about 30 kilometers per second, about the same
speed as Earth.
-
- The threats asteroids pose are real.
Famously, about 65 million years ago, life on Earth was brought to its knees by
what was likely the impact of a big asteroid, killing off most dinosaurs. Even
a four-meter object traveling at a relative speed of up to 60 kilometers per
second is going to pack a punch.
-
- How many asteroids hit Earth and how many
can we expect to zip past us?
Asteroid statistics and the
threats posed by asteroids of different sizes. NEOs are “near-Earth objects”,
any small body in the Solar System whose orbit brings it close to our planet.
From left to right the size of asteroid increased from 4 meters up to 10,000
meters, as does the frequency.
-
- Asteroid statistics and the threats posed
by asteroids of different sizes. NEOs are near-Earth objects, any small body in
the Solar System whose orbit brings it close to our planet. (Image credit:
NASA)
-
- Earth experiences frequent but low-impact
collisions with small asteroids, and rare but high-impact collisions with big
asteroids. In most cases, the smallest asteroids largely break up when they hit
Earth’s atmosphere, and don’t even make it down to the surface.
-
- When a small asteroid (or meteoroid, an
object smaller than an asteroid) hits Earth’s atmosphere, it produces a
spectacular “fireball”, a very long-lasting and bright version of a shooting
star, or meteor. If any surviving bits of the object hit the ground, they are
called “meteorites”. Most of the object burns up in the atmosphere.
-
- How many asteroids fly right past
Earth? Once per year, on average, a
four-meter asteroid will intersect the surface of Earth. If you doubled that surface area, you’d get
two per year. Earth’s radius is 6,400km. A sphere with twice the surface area
has a radius of 9,000km. So, approximately once per year, a four-meter asteroid
will come within 2,600 km of the surface of Earth – the difference between
9,000 km and 6,400 km.
-
- Double the surface area again and you could
expect two per year within 6,400 km of Earth’s surface, and so on. This tallies
pretty well with recent records of close approaches.
-
- Astronomers consider anything passing
closer than the Moon – approximately 300,000 km – to be a “close
approach”. In 2022 there were 126 close
approaches, and in 2023 we’ve had 50 so far.
-
- Now, consider really big asteroids, bigger
than one kilometer in diameter. The same highly simplified logic as above can
be applied. For every such impact that could threaten civilization, occurring
once every half a million years or so, we could expect thousands of near misses
(closer than the Moon) in the same period of time.
-
- Such an event will occur in 2029, when
asteroid 153814 (2001 WN5) will pass 248,700km from Earth. Approximately 95% of asteroids of size
greater than one kilometer are estimated to have already been discovered, and
the skies are constantly being searched for the remaining 5%.
-
- When a new one is found, astronomers take
extensive observations to assess any threat to Earth. The Torino Scale categorises predicted
threats up to 100 years into the future, the scale being from 0 (no hazard) to
10 (certain collision with big object).
-
- Currently, all known objects have a rating
of zero. No known object to date has had a rating above 4 (a close encounter,
meriting attention by astronomers).
-
-Technology has advanced to
the point we have a chance to do something if we ever do face a big number on
the Torino Scale. Recently, the DART mission collided a spacecraft into an
asteroid, changing its trajectory. In the future, it is plausible that such an
action, with enough lead time, could help to protect Earth from collision.
-
-
January 31, 2024 ASTEROID
- sample returned? 4312
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--- to:
------
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------ “Jim Detrick” -----------
--------------------- --- Wednesday, January 31,
2024
---------------------------------
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