Linked Questions

15 votes
2 answers
2k views

Why does the closest approach of star S2 to Sgr A* not appear to be near the focus of its elliptical orbit?

Phys.org's Very Large Telescope sees star dance around supermassive black hole, proves Einstein right links to several ESO videos, including The star S2 makes a close approach to the black hole at the ...
uhoh's user avatar
  • 30.7k
12 votes
2 answers
3k views

When the sun "enters" a constellation, doesn't it make it impossible to see that constellation?

I was reading on NASA's website about how the Babylonians came up with dividing the sky into different slices and picked a pattern of stars in each slice to represent it. This ties in to astrological ...
Magnus's user avatar
  • 327
9 votes
2 answers
3k views

In which direction does the ecliptic plane make an angle of 60 degrees with galactic plane?

In which direction does the ecliptic plane make an angle of 60 degrees with galactic plane? Is it toward the galactic center? (It can have any 360 degree orientation.)
P.sebastian Aby's user avatar
1 vote
2 answers
618 views

Where is the center of the Milky Way located?

I have downloaded a star database from this page (The HYG Database): http://astronexus.com/node/34 And all the stars have (among other parameters) their XYZ coordinates in parsecs according to this ...
Carlos Zamora's user avatar
15 votes
1 answer
3k views

What is it exactly about these flares of infrared light from Sgr A* that "confirms" it is a supermassive black hole?

CNET.com's SCI-TECH Scientists confirm a 'supermassive black hole' at the heart of our galaxy It's "mind-boggling", they say. This links to Astronomy.com's Scientists finally confirm the Milky Way ...
uhoh's user avatar
  • 30.7k
11 votes
1 answer
2k views

Why the blank wedges in this very early 21 cm map of the Milky Way? (Oort et al. 1958)

Jan Oort was a pioneer in radio astronomy. Wikipedia says: It has been written that “Oort was probably the first astronomer to realize the importance” of radio astronomy. “In the days before radio ...
uhoh's user avatar
  • 30.7k
6 votes
1 answer
345 views

Do we know what's "behind the Milky Way"?

If we do, how? And what are those objects on the other side of the galactic center? We can't see through the dense band of light and dust, but maybe in other spectrums the band is much less dense? But ...
Tudvari's user avatar
  • 163
4 votes
1 answer
552 views

How did they measure the distance to the center of our galaxy to 0.3% accuracy?

The abstract of A geometric distance measurement to the Galactic center black hole with 0.3% uncertainty (Open Access) says: We present a 0.16% precise and 0.27% accurate determination of R₀, the ...
uhoh's user avatar
  • 30.7k
4 votes
1 answer
284 views

How feasible is it that we could see the Central Black Hole Sgr A* occlude one of it's closely orbiting stars?

I'm thinking about the recent famous photo of a black hole, some months ago. It got me wondering if there isn't a way to more easily make a direct observation of these. We detect exoplanets in part ...
Stilez's user avatar
  • 1,022
2 votes
1 answer
254 views

How did they estimate the mass of Sgr A*'s companion G2 without knowing what it was?

Gizmodo.com's Astronomers Spot Unprecedented Flashes From Our Galaxy's Black Hole mentions Sgr A*'s companion gas cloud G2. That Wikipedia article says: First noticed as something unusual in ...
uhoh's user avatar
  • 30.7k
1 vote
1 answer
80 views

What spectral feature was used to confirm that S0-2 is "single and available"? What is Brγ?

The Phys.org article Astronomers discover S0-2 star is single and ready for big Einstein test describes the results of a careful analysis of radial velocity measurements of the star S0-2, which orbits ...
uhoh's user avatar
  • 30.7k
6 votes
0 answers
205 views

How far have stars been seen beyond the center of the Milky Way?

What lies near the center of the galaxy is of great interest and in recent times the motion of dozen(s) of stars at the center of our galaxy orbiting around Sgr A* have been measured in great detail. ...
uhoh's user avatar
  • 30.7k