JCC The All-New, All-Different JCC Astronomy Thread

100 billion galaxies? Nope. It's ten times that amount

So is this the missing mass of the universe? The ideas behind dark matetr can be dismissed?

 

A leaked report from NASA shows that the EmDrive works (space travel without fuel), although they're waiting for peer-reviews to come in before releasing it:
https://www.yahoo.com/news/impossible-spaceship-engine-called-emdrive-194534340.html

 

I was wondering that, too. Haven't seen any discussion of it anywhere

 

I posed this question and a few smart people chimed in and said that on a local level it matters not. Galaxies should still be flying apart as they do not have enough visible mass to stay together as they do.

 

Though other proposed theories do suggest that dark matter is no longer needed

http://www.nextbigfuture.com/2016/11/proposed-theory-of-emergent-gravity-to.html

 

I first read about MOND in 2001. In fact I had to go look it up as a rather smart fellow mentioned it casually while giving me Matrioshka Brain explanations.

 

There will be a new star in our skies in 2022

And it will be from the collision of two stars.

 

So it will be just off the line between Deneb and Vega, making it relatively easy to spot. Very, very cool.

 

a 2 billion pixel image of the Cat's Paw Nebula

There is a zoomable version in the article.

 

They're gonna try to make Pluto a planet again.

 

WIth this proposal, not only would be our moon classified as a planet, but also the larger moons of Jupiter, Saturn, Uranus and Neptun as well as some of the larger objects in the asteroid belt and Kuiper belt. Then we would have too many planets. I think they should stay with the current definition and have only eight planets. But that is apparently not acceptable for some american scientists.

 

I think they would need to add so long as it isn't already orbiting a planet.

 

I heard NASA is supposed an announcement tomorrow too? Or is this the same thing? (that link isn't working right now)

(and I'd rather have more than 9 planets than only 8... Pluto was always my favorite and it has only become more fascinating, let's make Ceres, Sedna and a few others officially count as planets too.)

 

No the announcement tomorrow has to do with extrasolar planets, or the rumors says.

 

A solar system with Earth-sized worlds

This has a nice size comparison chart.

 

Here's a better page



The white circles make it confusing. Ignore them. The black curved lines are the orbits of the worlds. Earth orbit to Mars orbit is around 45 million miles(the scale is a tad off here), so the worlds of Trappist orbit closer. Since the star is a dwarf the inner 3 worlds sit in the habitable zone.

 

This pic:

Spoiler

shows just how small it is compared to our own solar system.

 

So the infographic I posted above is bad. Pay it no mind.

 

It's relevant for the "temperatures" (received energy) of each potentially habitable zone, at least - so we know Trappist 1-h is experiencing about as dense an energy flux as the asteroid belt is.

 

A handy chart for moon comparison

 

You might have heard of using the Sun's focal point for telescopes at 550 AU

This article gives a parameter I have not seen before.

Instead of a single pixel or two, astronomers would get images of 1,000 x 1,000 pixels from exoplanets 30 parsecs, or about 100 light years, away. That translates to a resolution of about 10 kilometers on the planet’s surface, better than what the Hubble Space Telescope can see on Mars, which would allow us to make out continents and other surface features.

 

A white dwarf orbits a black hole as 1% the speed of light

A 2015 study suggested that X9's less-massive body might make one full orbit of the black hole in roughly 25 minutes. The new study agrees with that result: the researchers notice a periodic variation in the system’s X-ray brightness that takes about 28 minutes to go through a cycle.

 

A new close-up of Jupiter: