[QUOTE=firejuggler;499366]A sad week for space exploration[/QUOTE]I beg to differ. It is a wonderful week. These 2 missions that have gone on longer than expected have returned fabulous science that has helped up better understand the heavens. Dawn was a marvelous mission and the data will keep people occupied for some time.

Kepler did wonders. And when K2 was started it gave stats in even more of the sky. A little known fact is that Kepler in the K2 mission (along with Hubble, SOFIA, Cassini, and other NASA assets) supported New Horizons mission to Pluto. If it hadn't been in the K2 mode, it would not have been available.

When my last car died, I got a new and better one. Same thing should be done with spacecraft.

Bepi / Colombo just launched.
Parker solar probe is now the closest thing to the sun that people have made. It is now the fastest.
Insight is shortly to land on Mars (3 weeks or so), with small sub-spacecraft to boot!
New Horizons is less than 2 months away from its second Kuiper belt encounter (with an object that we know less about than its primary target.)
TESS has returned data.
Mars is a busy place.

It is a great time.

Dab your eyes, blow your nose, and move on.

[QUOTE=Uncwilly;499373]When my last car died, I got a new and better one. Same thing should be done with spacecraft.[/QUOTE]

But you can't just go to the spacecraft dealership and buy a new space telescope or planetary probe. Those things take a decade or two to design and build.

So what happens if the old ones are dying off and there isn't enough in the pipeline?

Having to retire a spacecraft because it has run out of fuel is an inevitable occurrence.

The Hubble space telescope is living on borrowed time. Sooner or later, it will cease to function. That wil be a sad day.

But that project overcame a major oopsadaisy with its mirror, and has undergone major repairs/upgrades. To put it mildly, it has exceeded expectations.

To me, the saddest thing about Hubble is that its launch was delayed so long, my father, who was very enthusiastic about it, never got to see it go up, let alone begin to fulfill its mission.

Now, the Webb Space Telescope has had [i]its[/i] launch delayed. It was scheduled to go up this year. But earlier this year it was put back till 2021.

[QUOTE=Uncwilly;499373]I beg to differ. It is a wonderful week. These 2 missions that have gone on longer than expected have returned fabulous science that has helped up better understand the heavens. Dawn was a marvelous mission and the data will keep people occupied for some time.

Kepler did wonders. And when K2 was started it gave stats in even more of the sky. A little known fact is that Kepler in the K2 mission (along with Hubble, SOFIA, Cassini, and other NASA assets) supported New Horizons mission to Pluto. If it hadn't been in the K2 mode, it would not have been available.

When my last car died, I got a new and better one. Same thing should be done with spacecraft.

Bepi / Colombo just launched.
Parker solar probe is now the closest thing to the sun that people have made. It is now the fastest.
Insight is shortly to land on Mars (3 weeks or so), with small sub-spacecraft to boot!
New Horizons is less than 2 months away from its second Kuiper belt encounter (with an object that we know less about than its primary target.)
TESS has returned data.
Mars is a busy place.

It is a great time.

Dab your eyes, blow your nose, and move on.[/QUOTE]

Yeah, i know about all of them (well except Parker). Bepi/Colombo is the one i look the most forward to. TESS come to a close second, as the data is not ( AFAIK) publicaly availlable yet... ( [url]https://www.zooniverse.org/projects/nora-dot-eisner/planet-finders[/url] )
The link above will let citizen scientist help finding exoplanet in TESS 's data. of course K2 data is still used [URL="https://www.zooniverse.org/projects/ianc2/exoplanet-explorers"]there [/URL]
And as Dr Sardonicus said, Hubble is on borrowed time, and suffered a shutdown recently (as well as chandra). Who will provide us nice picture if Hubble shut down permanently before JWT (James Web Telescope) is launched? ( I know that hubble is not the only one which can provide pretty picture, it just is the most know atm)

[url=https://prod-physicsworld-iop.content.pugpig.com/blog/2018/10/29/si-gets-a-makeover/pugpig_index.html]SI Gets a Makeover[/url] | Physics World
[quote]On 16 November 2018 metrologists and policy-makers from 60 countries around the world will gather at the General Conference on Weights and Measures (CGPM) in Versailles, France. Nothing unusual there, as the meeting convenes once every four years to discuss budgets and issues in metrology. But this meeting will be special. Member states will be voting on whether to adopt the most sweeping change to the International System of Units (Système International, or SI) since its inception in 1960. It is a change that will include new definitions of the kelvin, ampere and mole, but perhaps most significantly the kilogram.
...
Named after Max Planck, who developed the idea that energy comes in small packets called quanta, the Planck constant, h, relates the energy of one quantum of electromagnetic radiation to its frequency by the famous formula E = hν. The Planck constant is in turn linked to mass via Einstein’s E = mc2. Currently, h has a measured value of approximately 6.62607 × 10–34 m2 kg s–1, but [b]metrologists now want to fix its value in stone[/b], with the kilogram defined in terms of this value.[/quote]
I've bolded a rather unfortunate choice of metaphor in an article which is all about the problematic nature of defining one's units of measurement in terms of physical objects.

Also, if you read the details about the 2 independent methods currently used to measure Planck's constant (which technique will be flipped on its head by fixing h and instead letting it define the kg), there are plenty of physical objects involved - a moving coil of wire in one and "a uniform crystal of silicon-28 atoms that has been machined into almost a perfectly round 1 kg sphere" in the other - it's clear that the kg is really just being redefined in terms of physical objects in a way less fraught with error and changes-over-time than before. Which is fine so far as it goes, but I wonder if e.g. counting electrons or atoms of a single isotope of a given element lending itself to such monoisotopic purification might not have provided an alternate route to an unchanging kg which better fulfils Maxwell's quote cited in the piece:
[i]
“If…we wish to obtain standards of length, time and mass which shall be absolutely permanent, we must seek them not in the dimensions, or the motion, or the mass of our planet, but in the wavelength, the period of vibration, and the absolute mass of these imperishable and unalterable and perfectly similar molecules.”
[/i]
As part of the proposed slate of changes, the mole is similalrly being redefined in terms of "exactly 6.022,140,76 × 10^23 elementary entities", so if one can practically obtain a supply of exactly identical "elementary entities" and a suitable counting technique for same, there's your unvarying mass measure right there.

[QUOTE=ewmayer;499581][url=https://prod-physicsworld-iop.content.pugpig.com/blog/2018/10/29/si-gets-a-makeover/pugpig_index.html]SI Gets a Makeover[/url] | Physics World

I've bolded a rather unfortunate choice of metaphor in an article which is all about the problematic nature of defining one's units of measurement in terms of physical objects.

Also, if you read the details about the 2 independent methods currently used to measure Planck's constant (which technique will be flipped on its head by fixing h and instead letting it define the kg), there are plenty of physical objects involved - a moving coil of wire in one and "a uniform crystal of silicon-28 atoms that has been machined into almost a perfectly round 1 kg sphere" in the other - it's clear that the kg is really just being redefined in terms of physical objects in a way less fraught with error and changes-over-time than before. Which is fine so far as it goes, but I wonder if e.g. counting electrons or atoms of a single isotope of a given element lending itself to such monoisotopic purification might not have provided an alternate route to an unchanging kg which better fulfils Maxwell's quote cited in the piece:
[i]
“If…we wish to obtain standards of length, time and mass which shall be absolutely permanent, we must seek them not in the dimensions, or the motion, or the mass of our planet, but in the wavelength, the period of vibration, and the absolute mass of these imperishable and unalterable and perfectly similar molecules.”
[/i]
As part of the proposed slate of changes, the mole is similalrly being redefined in terms of "exactly 6.022,140,76 × 10^23 elementary entities", so if one can practically obtain a supply of exactly identical "elementary entities" and a suitable counting technique for same, there's your unvarying mass measure right there.[/QUOTE]

Fortunately the [URL="https://en.wikipedia.org/wiki/International_System_of_Units"]the US is not a member[/URL]. I imagine a voting member from the US to vote against anything that Il Duce disagrees with.

[QUOTE=rogue;499584]Fortunately the [URL="https://en.wikipedia.org/wiki/International_System_of_Units"]the US is not a member[/URL]. I imagine a voting member from the US to vote against anything that Il Duce disagrees with.[/QUOTE]Why would he disagree with it?

[QUOTE=rogue;499584]I imagine a voting member from the US to vote against anything that Il Duce disagrees with.[/QUOTE]

Like, perhaps, gravity... "It's all fake news! We're not pulled, we're pushed!

[QUOTE=chalsall;499586]Like, perhaps, gravity... "[] We're not pulled, we're pushed![/QUOTE]That might actually be true! No one seems to know how gravity works.

[QUOTE=chalsall;499586]Like, perhaps, gravity... "It's all fake news! We're not pulled, we're pushed![/QUOTE]Il Duce has a point there.

According to GR, the best theory of gravity we currently have, gravity is a quadrupolar interaction, not a bipolar one like electromagnetism. EM pushes and pulls, in other words, whereas gravity stretches and squeezes. If we lived in free fall, what Uncle Albert would term an inertial reference frame, all this would be intuitively obvious, but we don't. The surface of the earth is stopping us from moving in free fall and is, in effect, exerting a force on us to do so, We tend to call that force "gravity" but rather than ascribing it as the earth's surface pushing us away from our natural state of motion we describe it as the earth pulling us towards its center of mass.

[QUOTE=retina;499585]Why would he disagree with it?[/QUOTE]

He would do whatever it take to make sure that the standards benefit himself or the US directly. Facts and science don't matter to him. His war against supporters of climate change is a good example of that.