0.5 Ma as measure of time

[Guest Trying]

I am 50 years old and taking my very first science course ever. I love it, but my brain is going to explode. It's a university course for non-science students but they assume some minimal background knowledge that I don't have. So please excuse the simplistic questions I will ask.

 

I am studying for an exam and won't have access to the teacher beforehand. I probably don't really have to know this, but I really want to understand. Just the basics please because I don't even have high-school algerbra. I passed with a 60% 35 years ago.

 

I don't have an official textbook. In the notes I was given, in referring to the formation of stars, it states that a certain stage occured in less than 0.5 Ma, and then "a passive residual disk may persist in orbit around the protostar for a further 10Ma during which it evolves as a T Tauri star".

 

I tried searching google for "Ma as measure of time" but got all kinds of random stuff.

 

What is "Ma" and how can I relate it to regular time? I don't need a formula, I am just trying to conceptualize approximately how long .05 Ma is. Minutes, hours, years, centuries, billions of years?

 

Please don't give me a formula. I am already traumatized by learning powers of 10 notation and even worse, the equation for Hubble's law.

 

Which bodies have gravitational pull and which don’t, or does everything that has mass also have gravitational pull. What the heck is gravity? Do we know what it is or what it is caused by or do we just know that it exists?

 

Is there a simple way to answer my questions or would I have to know much more science to understand?

 

Thank-you very much in advance,

 

Infosaturated

[Douglas]

It sounds like .5 mA should be .5 mS... milliseconds ....5/1000th's of a second.

[timo]

a = year, M = mega = million => 1 Ma = 1 million years => .05 Ma = 50,000 years.

 

Which bodies have gravitational pull and which don’t, or does everything that has mass also have gravitational pull. What the heck is gravity? Do we know what it is or what it is caused by or do we just know that it exists?

Gravitational pull is proportional to the mass of an object, so all objects with mass exert a gravitational pull on others. Gravity is the feature of masses to attract each other.

It´s rather hard to answer your question whether we know what gravity is but I´d tend to the answer "no, we don´t". If you dig deep enough into any physical theory you´ll allways come to a point where you don´t know why something behaves like it does. In fact, physics is not about describing WHY things work, but about HOW they do. That´s what the formulas do.

[mezarashi]

The mA is most likely a unit of time, and my first guess would be in the millions of years rather than milliseconds. This *is* star formation. It took look a billion years or something for Earth to form after the Sun cooled down. So if it makes any sense, I would guess it to be 0.5 million years.

 

Your question on gravity. Yes, everything with mass in the universe is involved with gravity, meaning they are pulled in by other things, and they in turn pull other things towards them. The magnitude of which they pull depends on their mass. The bigger you are the harder you fall they say.

 

The question of 'what is gravity' is more profound I think. There probably isn't a final theory on all of this yet, but the best model for it as far as I know is Einstein's general relativity. Gravity is caused by the bending of the space-time continuum (the fabric) itself. The more simple explanation usually taught in highschool is that gravity is one of the four fundamental forces of the universe: gravity, weak, strong, electromagnetic. Gravity is like a property of mass, so all mass contributes to the gravitational field.

 

Goodluck in your studies ^^

[Spyman]

The small letter "m" stands for milli which is a part of a thousand (1/1000) and the large letter "M" stands for Mega which is a million (1000000).

 

The small letter "a" stands for Years which is time and the large letter "A" stands for Amperes which is current in electricity.

 

0.5Ma = 500 000 Years and 0.05Ma = 50 000 Years

 

In the headline You asked for 0.5Ma and then in the text .05Ma which likely is a misstype.

[Douglas]

a = year, M = mega = million => 1 Ma = 1 million years => .05 Ma = 50,000 years.

Thanks, I just learned something.

[Guest Trying]

Thank you very much for your help everyone. I think I did fairly well on my midterm:)