…actually tomorrow morning, but it’ll be easily visible most of the night.

>Mars reaches its closest approach to Earth for 11 years this evening at 21:35 GMT (7.35AM tomorrow AEST). The red planet will be just 75 million kilometres away.

Australia and New Zealand are the places to be for a good show. From there, Mars is high in the night sky. It can be found near the bright red star Antares and the yellow-tinged planet Saturn, forming a beautiful jewel-like triangle.

https://www.theguardian.com/science/across-the-universe/2016/may/30/mars-makes-closest-approach-to-earth-for-11-years

oooh! good omen for war maneuvres!!!!

Postpocelipse said:

oooh! good omen for war maneuvres!!!!

Yet across the gulf of space, minds that are to our minds as ours are to those of the beasts that perish, intellects vast and cool and unsympathetic, regarded this earth with envious eyes, and slowly and surely drew their plans against us.

AwesomeO said:

Postpocelipse said:

oooh! good omen for war maneuvres!!!!

Yet across the gulf of space, minds that are to our minds as ours are to those of the beasts that perish, intellects vast and cool and unsympathetic, regarded this earth with envious eyes, and slowly and surely drew their plans against us.

They will be sorely dissappointend. Frank has security tight as a wassies who’sit round here……..

AwesomeO said:

Postpocelipse said:

oooh! good omen for war maneuvres!!!!

Yet across the gulf of space, minds that are to our minds as ours are to those of the beasts that perish, intellects vast and cool and unsympathetic, regarded this earth with envious eyes, and slowly and surely drew their plans against us.

Before I look that up I’m guessing it’s from War of the Worlds.

Yay for me.

Although this is interesting, note that it won’t look detectably brighter than last week or next week.

Peak Warming Man said:

AwesomeO said:

Postpocelipse said:

oooh! good omen for war maneuvres!!!!

Yet across the gulf of space, minds that are to our minds as ours are to those of the beasts that perish, intellects vast and cool and unsympathetic, regarded this earth with envious eyes, and slowly and surely drew their plans against us.

Before I look that up I’m guessing it’s from War of the Worlds.

Yes. Great album as well.

dv said:

Although this is interesting, note that it won’t look detectably brighter than last week or next week.

bit like some folk in here…

stumpy_seahorse said:

dv said:

Although this is interesting, note that it won’t look detectably brighter than last week or next week.

bit like some folk in here…

ROFL

Mars was very purdy this morning when I left for work.

So will it be bigger than the Moon?

(when viewed through a huge telescope).

Mars is always bigger than the Moon.

I love hoaxes.

http://www.hoax-slayer.com/mars-earth-close.html

“Mars will look as large as the full moon to the naked eye.

Mars will be easy to spot.”

Imagine the tides if Mars got close enough to look like a full moon. (I guess it would be worse if Uranus got close enough to look like a full moon…)

Divine Angel said:

I love hoaxes.

http://www.hoax-slayer.com/mars-earth-close.html

“Mars will look as large as the full moon to the naked eye.

Mars will be easy to spot.”

Imagine the tides if Mars got close enough to look like a full moon. (I guess it would be worse if Uranus got close enough to look like a full moon…)

Would turn blue eyes brown

Divine Angel said:

Imagine the tides if Mars got close enough to look like a full moon. (I guess it would be worse if Uranus got close enough to look like a full moon…)

It’s never good when a full-moon shows Uranus.

Tidal effect is roughly proportional to mass divided cube of distance, whereas apparent width is proportional to diameter divided by distance.

So if you do the maths, it turns out that the tidal effect of a roughly spherical object placed so that it has the same apparent width as the moon will depend only on its density.

The tidal effect of Mars would be about 20% greater than the moon under those circumstances, whereas the effect of Uranus would only about about 35% that of the moon.

Witty Rejoinder said:

Divine Angel said:

Imagine the tides if Mars got close enough to look like a full moon. (I guess it would be worse if Uranus got close enough to look like a full moon…)

It’s never good when a full-moon shows Uranus.

gives new meaning to the moons of Uranus

it has 27

CrazyNeutrino said:

Witty Rejoinder said:

Divine Angel said:

Imagine the tides if Mars got close enough to look like a full moon. (I guess it would be worse if Uranus got close enough to look like a full moon…)

It’s never good when a full-moon shows Uranus.

gives new meaning to the moons of Uranus

it has 27

Inhabited by Klingons?

dv said:

Tidal effect is roughly proportional to mass divided cube of distance, whereas apparent width is proportional to diameter divided by distance.

So if you do the maths, it turns out that the tidal effect of a roughly spherical object placed so that it has the same apparent width as the moon will depend only on its density.

The tidal effect of Mars would be about 20% greater than the moon under those circumstances, whereas the effect of Uranus would only about about 35% that of the moon.

So, out of all the planets in the Solar System, Venus would have the greatest influence?

Divine Angel said:

dv said:

Tidal effect is roughly proportional to mass divided cube of distance, whereas apparent width is proportional to diameter divided by distance.

So if you do the maths, it turns out that the tidal effect of a roughly spherical object placed so that it has the same apparent width as the moon will depend only on its density.

The tidal effect of Mars would be about 20% greater than the moon under those circumstances, whereas the effect of Uranus would only about about 35% that of the moon.

So, out of all the planets in the Solar System, Venus would have the greatest influence?

Mercury

Oh of course. Der me.

( I should point out that there is a limit to the accuracy of this analysis which is basically approximating a difference of squares to a cube … you can’t generate big tides by putting a steel marble a few metres from the earth. Let’s say that these approximations will work pretty well above a distance of 100000 km or so.

Divine Angel said:

Oh of course. Der me.

If you weren’t a working mother you’d have known that.

dv said:

Divine Angel said:

Oh of course. Der me.

If you weren’t a working mother you’d have known that.

IKR. Think of all the space docos I could be watching on Netflix if I didn’t work.

Checking the density of planets other than Earth, I found this site:
http://www.universetoday.com/36935/density-of-the-planets/

which says that if the material wasn’t compressed by gravity, Mercury would be denser than Earth.

I wasn’t surprised by that, but I was surprised by the fairly small amount of increase in density.

Do we actually know how much increase in density is due to gravitational compression?

How do we know that?

The Rev Dodgson said:

Checking the density of planets other than Earth, I found this site:
http://www.universetoday.com/36935/density-of-the-planets/

which says that if the material wasn’t compressed by gravity, Mercury would be denser than Earth.

I wasn’t surprised by that, but I was surprised by the fairly small amount of increase in density.

Do we actually know how much increase in density is due to gravitational compression?

How do we know that?

Those estimates depend heavily on assumptions about what the planets are made of: these assumptions will be inaccurate but they can’t be too bad. If you key up a spatial model of what you think a roughly spherically symmetrical object is made of, it is pretty easy from basic mechanics to “switch” off the gravity and see what radius it decompresses to.