Interesting Space Facts.

[Skyrat]

About a year ago I learned about barycentres, and found it very interesting to learn that the dwarf planet Pluto, and its 'moon' Charon are actually a binary dwarf planet system. Instead of Charon orbiting Pluto, the two bodies orbit a point in space, because they are so similar in mass. I thought that was fascinating.

[jmorgan]

Earths and the Moon orbit in a similar way. The centre in inside the Earth.

[Eric Mc]

All objects that orbit each other do this. One doesn't orbit the other - they each orbit a common centre of mass. Obviously, if one of the objects is larger than the other, the common centre of mass will be closer to the large object. Think of it as a dumbbell with unequal weights at either end.

[jmorgan]

Should have been clearer. It is one method for detecting planets around stars, the wobble.

[Caruso]

scorp said:

Caruso said:

Time and Distance. One scenario is that even with much more advanced technology other intelligent life hasn't been able to find a way of travelling faster than light.

Maybe we are the most advanced life form that currently exists.

I think that's a distinct possibility. Earth had hundred of millions of years of evolution that resulted in amazing biodiversity but didn't result in intelligent life till very recently. Why didn't intelligent dinosaurs evolve? They had a far longer run up than mammals did. Or there may well be intelligent life forms out there, but they may not have the appetite for technology that humans have.

[jmorgan]

Dinos did not need to evolve past the path they were on perhaps.

Edit. of course they did evolve but they got stuck in a rut.

[Eric Mc]

Caruso said:

think that's a distinct possibility. Earth had hundred of millions of years of evolution that resulted in amazing biodiversity but didn't result in intelligent life till very recently. Why didn't intelligent dinosaurs evolve? They had a far longer run up than mammals did. Or there may well be intelligent life forms out there, but they may not have the appetite for technology that humans have.

Dinosaurs and mammals emerged at much around the same time - about 250 million years ago. There were plenty of mammals around all through the dinosaur era.

[MKnight702]

BrerRabbit said:

You can overcome vast distances it just takes time, resources and planning/forethought - hence the stepping stone analogy. Colonizing the Milky Way is doable even using fossil fuels which is why there is a paradox.

The 'time' taken to traverse the milky way being an insurmountable obstacle also displays a very anthropomorphic view and almost certainly wouldn't apply to Alien civilisations. 3 years would be nothing to a species that has an average life span of say 300 years.

All that aside, why no replicating probes? That in itself cancels out most of the arguments based upon time constraints.

Perhaps, if the multiverse theories are correct, these advanced aliens took one look at the interstellar distances and thought "nah, stuff that for a game, lets go to the next universe over as it's right next door". If you think that space is big, and it really is you know, then an infinite number or alternate universes is going to blow your mind. I could have 10 earths worth of resources and so could everyone else on the planet, all the room you need for a growing empire and it is just the other side of the boundary not years and years away, even at light speed.

[NDA]

ash73 said:

Hannah Waddingham was magnificent

I know her brother. That's a space fact.

[Hugo a Gogo]

black holes are not holes in any sense, just very dense objects

if the earth somehow magically collapsed and formed a black hole, it would be about the size of a large marble, 17mm

the moon would carry on orbiting it

if it happened to the sun, it would be 6km across, all the planets would also keep orbiting

[callyman]

Hugo a Gogo said:

if it happened to the sun, it would be 6km across, all the planets would also keep orbiting

Then just over 8 minutes later we'd all be asking who turned the light off?
Then a short while after it'd start getting extremely cold.

[K12beano]

Apparently the speed that the universe is expanding is accelerating - and we're all going to be ripped apart. Scientist from Portsmouth said on R4 PM anyway.

[annodomini2]

Hugo a Gogo said:

black holes are not holes in any sense, just very dense objects

if the earth somehow magically collapsed and formed a black hole, it would be about the size of a large marble, 17mm

the moon would carry on orbiting it

if it happened to the sun, it would be 6km across, all the planets would also keep orbiting

For the first part, we don't know,. We can infer their existence by various mechanisms, but we don't know what they are, most currently accepted theories state that the laws of physics break down in the centre of a black hole so if they are correct it could be anything.

For the second part, probably.

For the third part In a classical point newtonian sense yes, but it's not that simple, the light pressure and solar wind would disappear being the major changes

[Atomic12C]

annodomini2 said:

Hugo a Gogo said:

black holes are not holes in any sense, just very dense objects

if the earth somehow magically collapsed and formed a black hole, it would be about the size of a large marble, 17mm

the moon would carry on orbiting it

if it happened to the sun, it would be 6km across, all the planets would also keep orbiting

For the first part, we don't know,. We can infer their existence by various mechanisms, but we don't know what they are, most currently accepted theories state that the laws of physics break down in the centre of a black hole so if they are correct it could be anything.

We know that they are not 'holes'....a hole does not have the ability to generate such levels of gravity. (Without going in to the quantum mechanics of what is a hole/vacuum/empty space etc).

[annodomini2]

Atomic12C said:

annodomini2 said:

Hugo a Gogo said:

black holes are not holes in any sense, just very dense objects

if the earth somehow magically collapsed and formed a black hole, it would be about the size of a large marble, 17mm

the moon would carry on orbiting it

if it happened to the sun, it would be 6km across, all the planets would also keep orbiting

For the first part, we don't know,. We can infer their existence by various mechanisms, but we don't know what they are, most currently accepted theories state that the laws of physics break down in the centre of a black hole so if they are correct it could be anything.

We know that they are not 'holes'....a hole does not have the ability to generate such levels of gravity. (Without going in to the quantum mechanics of what is a hole/vacuum/empty space etc).

It's a 'hole' because everything that goes in doesn't come out, just like 'Dark' matter/energy, it's just a term to cover that we don't really know what it is.

[MKnight702]

K12beano said:

Apparently the speed that the universe is expanding is accelerating - and we're all going to be ripped apart. Scientist from Portsmouth said on R4 PM anyway.

Don't tell Brake, they'll be campaigning for speed limits and cameras to be sent to the nearest galaxies toute suite!

[Sheets Tabuer]

To make the sun a black hole you'd need to compress it to the size of a city, there are black holes out there so large their diameter is 1600 times the distance of pluto.

[ChocolateFrog]

When Andromeda and The Milky Way galaxies collide despite there being billions of stars in each it is a near certainty that they'll pass through each other without any collisions.

[colin_p]

Not so much about space itself but getting there. I'm sure someone (who knows much more)on here at one point has already linked this; Apollo 11 launch at 500fps, mankinds mightiest machine which was last used back in the 70's. The shuttle and others may be newer but nothing compares, in my mind, to the Saturn V, which was likely designed and built largely using feet, inches and a slide rule.

https://www.youtube.com/watch?v=_eB82KvuesQ

A bit like firing up the mighty Passat 1.9 PD TDI on a cold morning except that doesn't set fire to my garage but only leaves a faint smudge of soot. It does provide a similar level of drama and satisfaction though.

[jmorgan]

colin_p said:

Not so much about space itself but getting there. I'm sure someone (who knows much more)on here at one point has already linked this; Apollo 11 launch at 500fps, mankinds mightiest machine which was last used back in the 70's. The shuttle and others may be newer but nothing compares, in my mind, to the Saturn V, which was likely designed and built largely using feet, inches and a slide rule.

https://www.youtube.com/watch?v=_eB82KvuesQ

A bit like firing up the mighty Passat 1.9 PD TDI on a cold morning except that doesn't set fire to my garage but only leaves a faint smudge of soot. It does provide a similar level of drama and satisfaction though.

On the DVD you can buy And more........

Crank up the surround sound and get the house vibrating like hell.

It is immense.