Astronomy

[Dreamwoven]

The SOCIETY for POPULAR ASTRONOMY

Electronic News Bulletin No. 456 2017 November 5

FRESH FINDINGS FROM CASSINI
NASA

The Cassini spacecraft ended its journey on Sept. 15 with an intentional
plunge into the atmosphere of Saturn, but analysis continues on the
mountain of data the spacecraft sent during its long 'life'. The
spacecraft's Ion and Neutral Mass Spectrometer (INMS) returned a lot
of direct measurements of the components in Saturn's upper atmosphere,
which stretches almost to the rings. From those observations, the team
sees evidence that molecules from the rings are raining down onto the
atmosphere. That influx of material from the rings was expected, but
INMS data show hints of ingredients more complex than just water, which
makes up the bulk of the rings' composition. In particular, the
instrument detected methane, a volatile molecule that scientists would
not expect to be abundant in the rings or found so high in Saturn's
atmosphere.

Chief among the questions that scientists hope to answer by using data
from Cassini is the age and origin of the rings. Theoretical modelling
has shown that, without forces to confine them, the rings would spread
out over hundreds of millions of years -- much younger than Saturn
itself. Such spreading happens because faster-moving particles that
orbit closer to Saturn occasionally collide with slower particles on
slightly farther-out orbits. When that happens, some momentum from the
faster particles is transferred to the slower particles, speeding the
latter up in their orbit and causing them to move farther out. The
inverse happens to the faster, inner particles. Previous research had
shown that gravitational tugs from the moon Mimas are solely responsible
for halting the outward spread of Saturn's B ring -- that ring's outer
edge is defined by the dark region known as the Cassini Division. Ring
scientists had thought that the small moon Janus was responsible for
confining the outer edge of the A ring, but a new modelling study shows
that the A ring's outward creep is kept in check by a confederation of
moons, including Pan, Atlas, Prometheus, Pandora, Janus, Epimetheus and
Mimas.

[Dreamwoven]

The SOCIETY for POPULAR ASTRONOMY

Electronic News Bulletin No. 456 2017 November 5

FRESH FINDINGS FROM CASSINI
NASA

The Cassini spacecraft ended its journey on Sept. 15 with an intentional
plunge into the atmosphere of Saturn, but analysis continues on the
mountain of data the spacecraft sent during its long 'life'. The
spacecraft's Ion and Neutral Mass Spectrometer (INMS) returned a lot
of direct measurements of the components in Saturn's upper atmosphere,
which stretches almost to the rings. From those observations, the team
sees evidence that molecules from the rings are raining down onto the
atmosphere. That influx of material from the rings was expected, but
INMS data show hints of ingredients more complex than just water, which
makes up the bulk of the rings' composition. In particular, the
instrument detected methane, a volatile molecule that scientists would
not expect to be abundant in the rings or found so high in Saturn's
atmosphere.

Chief among the questions that scientists hope to answer by using data
from Cassini is the age and origin of the rings. Theoretical modelling
has shown that, without forces to confine them, the rings would spread
out over hundreds of millions of years -- much younger than Saturn
itself. Such spreading happens because faster-moving particles that
orbit closer to Saturn occasionally collide with slower particles on
slightly farther-out orbits. When that happens, some momentum from the
faster particles is transferred to the slower particles, speeding the
latter up in their orbit and causing them to move farther out. The
inverse happens to the faster, inner particles. Previous research had
shown that gravitational tugs from the moon Mimas are solely responsible
for halting the outward spread of Saturn's B ring -- that ring's outer
edge is defined by the dark region known as the Cassini Division. Ring
scientists had thought that the small moon Janus was responsible for
confining the outer edge of the A ring, but a new modelling study shows
that the A ring's outward creep is kept in check by a confederation of
moons, including Pan, Atlas, Prometheus, Pandora, Janus, Epimetheus and
Mimas.

[Danik 2016]

Interesting article:

"Building on Dawn's findings, the team has
hypothesized that water vapour may be produced in part from energetic
particles from the Sun interacting with ice at shallow depths in Ceres'
surface."
That seems to me to be the most important aspect of the mission. Another concern is the composition of Ceres.

[Danik 2016]

The SOCIETY for POPULAR ASTRONOMY

Electronic News Bulletin No. 456 2017 November 5

FRESH FINDINGS FROM CASSINI
NASA

The Cassini spacecraft ended its journey on Sept. 15 with an intentional
plunge into the atmosphere of Saturn, but analysis continues on the
mountain of data the spacecraft sent during its long 'life'. The
spacecraft's Ion and Neutral Mass Spectrometer (INMS) returned a lot
of direct measurements of the components in Saturn's upper atmosphere,
which stretches almost to the rings. From those observations, the team
sees evidence that molecules from the rings are raining down onto the
atmosphere. That influx of material from the rings was expected, but
INMS data show hints of ingredients more complex than just water, which
makes up the bulk of the rings' composition. In particular, the
instrument detected methane, a volatile molecule that scientists would
not expect to be abundant in the rings or found so high in Saturn's
atmosphere.

Chief among the questions that scientists hope to answer by using data
from Cassini is the age and origin of the rings. Theoretical modelling
has shown that, without forces to confine them, the rings would spread
out over hundreds of millions of years -- much younger than Saturn
itself. Such spreading happens because faster-moving particles that
orbit closer to Saturn occasionally collide with slower particles on
slightly farther-out orbits. When that happens, some momentum from the
faster particles is transferred to the slower particles, speeding the
latter up in their orbit and causing them to move farther out. The
inverse happens to the faster, inner particles. Previous research had
shown that gravitational tugs from the moon Mimas are solely responsible
for halting the outward spread of Saturn's B ring -- that ring's outer
edge is defined by the dark region known as the Cassini Division. Ring
scientists had thought that the small moon Janus was responsible for
confining the outer edge of the A ring, but a new modelling study shows
that the A ring's outward creep is kept in check by a confederation of
moons, including Pan, Atlas, Prometheus, Pandora, Janus, Epimetheus and
Mimas.

That´s a new idea for me, that Saturns rings are kept in check by moons. The universe has its own balance.

[Dreamwoven]

On a similar theme - Hubble has discovered a dozen previously unknown moons going round Jupiter:

See Astronomy Now.

Astronomers searching for a hypothesised large planet in the outer Solar System far beyond Pluto stumbled across 12 previously undetected moons orbiting Jupiter, pushing the giant planet’s total to a record 79.

[Dreamwoven]

See Astronomy Now

Astronomers searching for a hypothesised large planet in the outer Solar System far beyond Pluto stumbled across 12 previously undetected moons orbiting Jupiter, pushing the giant planet’s total to a record 79.

[Danik 2016]

79 moons is quite a lot. But it definitely takes away the romantic aura of this heavenl body.

[Dreamwoven]

On a similar theme - Hubble has discovered a dozen previously unknown moons going round Jupiter:

From: Astronomy Now <[email protected]>
Subject: 12 new moons found orbiting Jupiter
Date: 17 July 2018 at 20:07:44 GMT+2
Reply-To: Astronomy Now <[email protected]>

[Dreamwoven]

The James Webb Telescope keeps getting postponed. Today the next postponement was announced. See https://www.universetoday.com/139620...nt-gas-giants/

[Dreamwoven]

So the Hubble Telescope remains the main space telescope we have.

[Dreamwoven]

The James Webb Space telescope will be concentrating on examining variations in planets that have some kind of atmosphere, to ascertain what its potential will be for its suitability to support life.

[tailor STATELY]

Saw a short on the James Webb Space telescope on NOVA last night. It has nearly 2 ounces of gold on its receiver as a coating 600 atoms thick ! Must be nightmare to calibrate.

Ta ! (short for tarradiddle),
tailor STATELY

[Danik 2016]

"The James Webb Space Telescope is like the party of the century that keeps getting postponed. Due to its sheer complexity and some anomalous readings that were detected during vibration testing, the launch date of this telescope has been pushed back many times – it is currently expected to launch sometime in 2021."

I think it must be a money matter too. I somehow have the, maybe wrong idea, that NASA is doing less research this year.

[Danik 2016]

Her is a bit more about the 12 Jupiter moons:

https://www.skyandtelescope.com/astr...-79-now-known/

[Danik 2016]

Astronaut news!

NASA Will Announce Commercial Crew Astronaut Picks

"Boeing's Starliner and SpaceX's Crew Dragon spacecraft will soon have their first riders: NASA plans to announce on Aug. 3 the astronauts assigned to the test flights and maiden voyages of the agency's commercial crew program.

NASA will air the event live from Johnson Space Center (JSC) in Houston starting at 11 a.m. EDT (1500 GMT), where NASA Administrator Jim Bridenstine will introduce the astronauts. JSC Director Mark Geyer and Kennedy Space Center Director Bob Cabana, as well as representatives from SpaceX and Boeing, will also be involved, NASA officials said in a statement. The program will reveal the astronauts assigned to each of the companies' crewed test flights and their first missions to the space station, which will all launch from Kennedy Space Center in Florida."
https://www.space.com/41288-nasa-wil...stronauts.html