AstroDistance

✖
`AstroDistance`

[Experimental]

✖

AstroDistance[astro]

returns the physical distance to the astronomical object astro as currently observed from your geo location.

✖

AstroDistance[astro,astro₀]

returns the physical distance to the astronomical object astro as currently observed from astro₀.

✖

AstroDistance[astro,Dated[astro₀,date]]

returns the physical distance to astro as observed from astro₀ on the given date.

Details

AstroDistance computes distances between specific locations moving through space, such as centers of celestial bodies or points on their surfaces.
In AstroDistance[astro₁,astro₀], the astro objects are given as astronomical entities, such as Entity["Planet","Mars"], representing the center of the celestial body, or as locations referred to their surface, such as GeoPosition[{lat,lon,h},"Mars"] or Entity["SolarSystemFeature", "OlympusMonsMars"]. Strings representing physical locations, such as "JupiterBarycenter", can also be used.
In AstroDistance[astro,astro₀], the observation astro₀ must be a location within the solar system, but the target location astro can be a deep-sky object, such as stars or galaxies.
The instant of observation, in the BCRS coordinates of the solar system, is determined by the second argument of AstroDistance, and it will be taken to be the current instant by default.
In AstroDistance[astro,astro₀], for astro objects outside the solar system, the result is always astrometric, i.e. giving the distance to the location from which the light was emitted and not to the location where astro was at the observation date.
In AstroDistance[astro,astro₀], for astro objects in the solar system, the result is corrected for light time by default, but can be made geometric using AstroDistance[astro,{astro₀,"LightTime""Geometric"}].

Examples

open allclose all

Basic Examples (3)Summary of the most common use cases

Find the current distance to the center of Venus from your geo location:

In[1]:=1

✖

https://wolfram.com/xid/0g7ibutkrgy-fk8oop

Out[1]=1

Find the distance to the center of Venus as observed from a point on the surface of the Moon:

In[1]:=1

✖

https://wolfram.com/xid/0g7ibutkrgy-yt2kyd

Out[1]=1

Plot the distance between the centers of Jupiter and Earth, between years 2015 and 2030:

In[1]:=1

✖

https://wolfram.com/xid/0g7ibutkrgy-pdpc1f

Out[1]=1

Scope (5)Survey of the scope of standard use cases

Find the distance to the center of Jupiter as currently measured from the center of Mars:

In[1]:=1

✖

https://wolfram.com/xid/0g7ibutkrgy-ncp3kb

Out[1]=1

This can also be expressed in these alternative forms:

In[2]:=2

✖

https://wolfram.com/xid/0g7ibutkrgy-1jo55p

Out[2]=2

In[3]:=3

✖

https://wolfram.com/xid/0g7ibutkrgy-2asmoc

Out[3]=3

Find the distance to the center of Jupiter from a point on the surface of Venus:

In[1]:=1

✖

https://wolfram.com/xid/0g7ibutkrgy-qalxo1

Out[1]=1

Compare with the distance between centers:

In[2]:=2

✖

https://wolfram.com/xid/0g7ibutkrgy-r6kuui

Out[2]=2

The difference is smaller than the radius of Venus, depending on the current geometric configuration:

In[3]:=3

✖

https://wolfram.com/xid/0g7ibutkrgy-dgrysv

Out[3]=3

Use geo entities for locations on the surface of the Earth or entities representing solar system features:

In[1]:=1

✖

https://wolfram.com/xid/0g7ibutkrgy-d8s3d8

Out[1]=1

Compute the between the Sun and the solar system barycenter:

In[1]:=1

✖

https://wolfram.com/xid/0g7ibutkrgy-mlqv1h

Out[1]=1

Compute the distance for the next 100 years, in units of gigameters, or millions of kilometers:

In[2]:=2

✖

https://wolfram.com/xid/0g7ibutkrgy-qt105p

Out[2]=2

Compute distances to a list of astronomical objects:

In[1]:=1

✖

https://wolfram.com/xid/0g7ibutkrgy-r2polj

Out[1]=1

The result is given in QuantityArray form:

In[2]:=2

✖

https://wolfram.com/xid/0g7ibutkrgy-n9p1y4

Out[2]=2

Use Normal to convert it to a list of Quantity distances:

In[3]:=3

✖

https://wolfram.com/xid/0g7ibutkrgy-fs25ke

Out[3]=3

Applications (4)Sample problems that can be solved with this function

Construct a function that computes the geometric distance between the centers of Jupiter and Earth for a given Gregorian year:

In[1]:=1

✖

https://wolfram.com/xid/0g7ibutkrgy-qjq6bh

Plot that distance between years 2020 and 2026:

In[2]:=2

✖

https://wolfram.com/xid/0g7ibutkrgy-q789kv

Out[2]=2

Find the instant of closest approach in 2022:

In[3]:=3

✖

https://wolfram.com/xid/0g7ibutkrgy-8zg4uv

Out[3]=3

In[4]:=4

✖

https://wolfram.com/xid/0g7ibutkrgy-pju1te

Out[4]=4

Convert to the standard Gregorian calendar:

In[5]:=5

✖

https://wolfram.com/xid/0g7ibutkrgy-ug7c5w

Out[5]=5

This is the distance between the Earth and the Sun for day d of year 2022:

In[1]:=1

✖

https://wolfram.com/xid/0g7ibutkrgy-m9qxry

Due to the eccentricity of Earth's orbit, the distance oscillates around 1 AU during a year:

In[2]:=2

✖

https://wolfram.com/xid/0g7ibutkrgy-m0ptvx

Out[2]=2

The perihelion of a planet is defined as the moment of closest approach to the Sun:

In[3]:=3

✖

https://wolfram.com/xid/0g7ibutkrgy-dwjuvp

Out[3]=3

In 2022 it happened on January 4, around 7am GMT:

In[4]:=4

✖

https://wolfram.com/xid/0g7ibutkrgy-g0bzpc

Out[4]=4

The aphelion is defined as the moment of maximum distance to the Sun:

In[5]:=5

✖

https://wolfram.com/xid/0g7ibutkrgy-8j6ra9

Out[5]=5

In 2022 it happened on July 4, also around 7am GMT:

In[6]:=6

✖

https://wolfram.com/xid/0g7ibutkrgy-dqi5c0

Out[6]=6

Find the distance to the star Vega:

In[1]:=1

✖

https://wolfram.com/xid/0g7ibutkrgy-zq1yaf

Out[1]=1

In[2]:=2

✖

https://wolfram.com/xid/0g7ibutkrgy-p6urjo

Out[2]=2

Compare to the distance observed from the Sun:

In[3]:=3

✖

https://wolfram.com/xid/0g7ibutkrgy-p205da

Out[3]=3

It oscillates around 1 AU as the Earth orbits around the Sun during a year:

In[4]:=4

✖

https://wolfram.com/xid/0g7ibutkrgy-lq3du3

Out[4]=4

The distance from the Sun also changes in time, due to proper motion of the star:

In[5]:=5

✖

https://wolfram.com/xid/0g7ibutkrgy-3sfgu1

Out[5]=5

The distance is decreasing about 2.5 au per year, as reflected by the negative radial velocity of Vega:

In[6]:=6

✖

https://wolfram.com/xid/0g7ibutkrgy-mmd68h

Out[6]=6

Compare the relative size of the Sun as currently observed from the different planets:

In[1]:=1

✖

https://wolfram.com/xid/0g7ibutkrgy-oi8o0v

Out[1]=1

In[2]:=2

✖

https://wolfram.com/xid/0g7ibutkrgy-7s1y1m

Out[2]=2

In[3]:=3

✖

https://wolfram.com/xid/0g7ibutkrgy-w0jqd0

Out[3]=3

Properties & Relations (3)Properties of the function, and connections to other functions

AstroDistance[astro,obsrvr] is equivalent to AstroPosition[astro,obsrvr]["Distance"]:

In[1]:=1

✖

https://wolfram.com/xid/0g7ibutkrgy-vrsonn

In[2]:=2

✖

https://wolfram.com/xid/0g7ibutkrgy-s19y8s

Out[2]=2

In[3]:=3

✖

https://wolfram.com/xid/0g7ibutkrgy-zwj29g

Out[3]=3

In[4]:=4

✖

https://wolfram.com/xid/0g7ibutkrgy-030fft

Out[4]=4

In[5]:=5

✖

https://wolfram.com/xid/0g7ibutkrgy-yas94b

Out[5]=5

AstroDistance[astro₁,astro₂] takes into account the time that light takes to propagate from astro₁ to astro₂. Compute the distance at which Jupiter can be seen from Mars on this date: