James K
  • Member for 7 years, 4 months
  • Last seen this week
Table of absolute magnitudes of stars by spectral type and photometric band
1 votes

There are a lot of stars [citation needed] and they are organised into catalogs by various organisations, well known catalogs include the UNSO catalog (produced by the united states Naval office) and ...

View answer
Could gravity waves be used to confirm the existence of a ninth planet?
1 votes

The maths on Wikipedia give a way of calculating the the amplitude of graviational waves. One detail is that for the waves to be detected by a ligo apparatus, one needs to be far enough from the ...

View answer
Why do planets move in an elliptical orbit?
1 votes

You probably know how things fall when they are thrown: A ball follows a curved path known as a parabola, the path of a ball is not circular, and it is certainly not a circle centred on the middle of ...

View answer
Is the colour of a wave from a far galaxy the same for us as for a galaxy which lies between?
1 votes

The light from distant galaxies is redshifted because they are moving away from us and the more distant the galaxy is the faster it moves, and so the more the light is redshifted. A galaxy between us ...

View answer
What is spacetime 'made' of?
1 votes

A mathematicial primer. A triangle on a flat surface has three angles, and these three angles add up to 180degrees - This is a well known theorem from geometry. It is also well known that if you ...

View answer
Can "dark matter" be the additional mass from the speed of the Galactic Cluster?
1 votes

The first part, "could the galactic cluster orbit another at 10000000km/h". Is no. For simple observational reasons. If the local group were in orbit, we would be able to see and measure the ...

View answer
Can earth escape sun's gravity with the help of a black hole heading towards our solar system?
1 votes

There is no need to hypothesise a black hole. A black hole's gravity is indistinguishable from that of a similarly sized star, except in the region closely surrounding the event horizon. Black holes ...

View answer
Betelgeuse and sun classification
1 votes

Type M is a spectral class: that is a star colour. Type M stars are red, and relatively cool. There are, roughly, two types of stars that are Type M: Main sequence stars that are small, have ...

View answer
Software to convert RA and DEC into ALT and AZ
1 votes

Minutes of a degree are "minúte". There are a few things that could cause errors. One is atmospheric refraction: it can cause an error of about 1 minute at the an alt of 45degrees, and over 30minutes ...

View answer
Was that actually a shooting star during the supermoon eclipse on September 27th 2015?
1 votes

There are about 5 sporadic meteors visible per hour most nights, and since thousands of people were taking photographs of the moon that night, it is not impossible that someone captured a meteor in ...

View answer
How do rogue planets orbit around stars in other planetary systems?
1 votes

Capture of any object is never common. A rogue planet that passes a star will be accelerated by the star's gravity, and provided that it doesn't hit anything will pass the star in a hyperbolic path. ...

View answer
Equation to find distance between objective and eyepiece
1 votes

Astronomical objects are so far away that they focus the same point as an object at infinite distance. In fact any object more than a hundred metres away or so can be treated as being an infinite ...

View answer
What are the stars/constellations a beginner/enthusiast can easily identify?
Accepted answer
1 votes

It varies throughout the year. A book or a website with maps will help. In Spring, Leo and Boötes dominate the southern skies, with Coma Berencies between them In Summer, the summer triangle of ...

View answer
Is it accurate to compare comets to clouds and rain?
1 votes

Dating cometary material is tricky, just because you have to go to space to get it. But the dates from the "stardust" mission show that comets are very very old. As old as the oldest asteroids, and ...

View answer
What is the share of stars in total radiation input of Earth?
1 votes

It is negligible. The amount of energy per square metre per second is called the "flux". The flux of the brightest star in the sky, Sirius, is one ten billionth of the sun. That mean the energy the ...

View answer
How do scientists name space objects?
1 votes

Names are only what we agree to call things. Astronomers have a practical need for names, and a romantic sense of discovery being confirmed by the naming. So Astronomers have cooperated to agree on ...

View answer
Volcano activity on moon
1 votes

The grey areas are known as "maria" (singular:"mare") and they were formed from flood basalts. These are a type of volcano and they have formed on earth too, examples include the lake eruption on ...

View answer
Is the time lapse considered when estimating the age of the universe?
Accepted answer
1 votes

As relativistic effects will cause clocks to run slower, a frame of reference must be chosen when considering the time of the "big bang". There is a natural and convenient choice of reference frame, ...

View answer
Is antimatter also attracted by gravitational field?
1 votes

The consensus opinion of physicists is that antimatter has mass, and it is attracted to other massive objects by gravity in exactly the same way as matter: Antimatter isn't anti-gravity. Proving this ...

View answer
Finding a location using the direction of shadow, UT and date approximately
1 votes

Planetarium software, such as Stellarium, or astronomical computation software such as pyephem can compute the exact position of the sun at any date, time and location. It is then simple trigonometry ...

View answer
Brightest star of the night sky
1 votes

Sirius is the brightest "star" in the night sky, but not the brightest object in the sky in the early morning, at the time of writing. In autumn of 2015, Venus is a very bright in the early morning ...

View answer
International Space Station
1 votes

The iss is orbiting around the earth, but even as it does so, the earth is rotating, and the orbital rate of the iss is not aligned to the rotation of the earth. The effect is that the track that the ...

View answer
What is the brightest star (relative magnitude) in M31?
Accepted answer
1 votes

The Variable stars that Hubble studied in M31 when he showed that it was a galaxy are among the most luminous. They include Var-A1, a luminous blue variable, and magnitude about 16.5. Var A-1 is one ...

View answer
Can we know where (South, East, West...) the moon will be at a specific time?
Accepted answer
1 votes

A planetarium programme will tell you exactly where to look, and can be invaluable when looking for the location of planets, but the Moon is very easy to find in the sky, even after several glasses of ...

View answer
If I were to point into the sky, how many galaxies would be in this line?
1 votes

Take a look at the "Deep field" image from Hubble: http://www.spacetelescope.org/science/deep_fields/ You can see in this tiny part of the sky, hundreds of galaxies, but between there is lots of dark ...

View answer
What known comets are binary?
1 votes

Contact binaries, in which two objects are touching may be fairly common. This is one interpretation of the "rubber duck" shape of the "Rosetta comet" 67P/Churyumov–Gerasimenko, and radar observation ...

View answer
Contradict the expansion of the universe?
1 votes

Such a group is called a discordant redshift group. It could be the case that the exceptional galaxy is not a true member of the cluster. The famous example of this is Seyfert's sextet. Five of the ...

View answer
Was the young Sun cooler or hotter than it is today?
0 votes

Yes, both. As a protostar, the sun formed from a collapsing ball of gas. In this state the sun's total luminosity was very high, and it would be called a T-Tauri object. Then it followed the "...

View answer
Can Quantum tunneling be possible within Blackhole ? And if so, could that be the source of Dark Energy?
0 votes

Tunneling isn't possible, because the event horizon isn't a "forbidden region" with "permitted regions on both sides". In tunnelling you have a potential wall. Classical ...

View answer
Why doesn't the night sky keep on getting brighter and brighter every day?
0 votes

This assumes that the stars formed at the same time as the Earth. This is not the case. Stars had been forming for billions of years since the Earth formed. The Earth didn't form in a single day, ...

View answer