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Elliptical Transfer-Intercept Orbits

Non-Hohmann Transfer Orbits that Take You Somewhere

Most of the time, when someone speaks of transfer orbits, he's referring to a special case known as a Hohmann transfer orbit. Hohmann transfer orbits have a departure occurring at one of its apsides (perihelion or aphelion) and an arrival occurring at the other apside. Thus, I could describe Hohmann transfer orbits as transfer orbits having two anchored apsides.

In practice, very few interplanetary transfer orbits will be Hohmann transfers. The orbits of solar system bodies are ellipses, not circles, and the planes in which the orbits exist are tilted with respect to each other. The direction in which a rocket must apply thrust, in order to enter a transfer orbit bound for an asteroid that is almost in the ecliptic plane might be, itself, in an angular sense, quite far from the ecliptic plane.

In this essay, I will treat a more general case of transfer orbits that have only one anchored apside, which turns out to be enough to close the equation set and permit the Keplerian elements of the transfer orbit to be found, as well as the changes of velocity required for transfer orbit insertion and, later, for matching velocity with the destination object.

In what follows, the following example problem will be used for illustration:


A spaceship is initially in Earth's orbit, but is on the opposite side of the sun from Earth. Its captain wants to enter a transfer orbit, bound for Vesta, at 12h UT on 26 June 2017. The navigator does some trial runs on a computer and discovers an elliptical transfer orbit having its aphelion at Vesta upon arrival at 4h 45m 36.036s UT on 12 June 2018. Check the navigator's work to ensure that an elliptical transfer orbit does exist for these times for departure and arrival. Show the elements of the transfer orbit and the delta-vees required for transfer orbit insertion (departure) and for matching velocity with Vesta at arrival.

Spaceship initial orbit.
a = 1.000002 AU
e = 0.016711
i = 0.0°
Ω = 0.0°
ω = 103.095°
T = JD 2454285.96

Vesta's orbital elements.
a = 2.36126914 AU
e = 0.089054753
i = 7.13518389°
Ω = 103.91484282°
ω = 149.85540185°
T = JD 2454267.1969204

Departure time,
t₁ = 12h UTC, 26 June 2017

Arrival time,
t₂ = 4h 45m 36.036s UTC, 12 June 2018


It is convenient to convert t₁ and t₂ from calendar date format to Julian date format.


Converting from Calendar Date to Julian Date

After Fliegel and van Flandern (1968).

The time zone must be Greenwich, Zulu, UT, UTC (all the same zone)

Y = the four-digit year
M = the month of the year (1=January... 12=December)
D = the day of the month
Q = the time of the day in decimal hours

A = integer [ (M−14) / 12 ]
B = integer { [ 1461 (Y + 4800 + A) ] / 4 }
C = integer { [ 367 (M − 2 − 12A) ] / 12 }
E = integer [ (Y + 4900 + A) / 100 ]
F = integer [ (3E) / 4 ]
t = B + C − F + D − 32075.5 + Q/24

Converting the time of departure, t₁, from calendar date to Julian date

t₁ = 12h UTC, 26 June 2017
Y = 2017
M = 6
D = 26
Q = 12
A = 0
B = 2489909
C = 122
E = 69
F = 51
t₁ = JD 2457931.0


Converting the time of arrival, t₂, from calendar date to Julian date

t₂ = 4h 45m 36.036s UTC, 12 June 2018
Y = 2018
M = 6
D = 12
Q = 4.76001
A = 0
B = 2490274
C = 122
E = 69
F = 51
t₂ = JD 2458281.69833375


Instead of having the initial position vectors given to us, we must calculate them by reducing the elements of the spaceship's initial orbit (around the sun) and the time of departure therefrom, t₁, in order to obtain the position vector r₁, and by reducing the elements of Vesta's orbit and the time of arrival thereto, t₂, in order to obtain the position vector r₂.

For what passes below, the Sun's gravitational parameter,

GM = 1.32712440018ᴇ20 m³ sec⁻²

The ratio of the astronomical unit to the meter,

AU = 1.495978707ᴇ11 m au⁻¹

And the

Definition of the two-dimensional arctangent function.

atn(z) = single argument arctangent function of the argument z.

Function arctan( y , x )
. if x = 0 and y greater than 0 then angle = +π/2
. if x = 0 and y = 0 then angle = 0
. if x = 0 and y less than 0 then angle = −π/2
. if x greater than 0 and y greater than 0 then angle = atn(y/x)
. if x less than 0 then angle = atn(y/x) + π
. if x greater than 0 and y less than 0 then angle = atn(y/x) + 2π
arctan = angle

Unless otherwise indicated, the coordinate system to which all unprimed vectors in this essay refer is ecliptic coordinates — heliocentric for position, and sun-relative for velocity.


Reducing Keplerian orbital elements and a time to position and velocity in heliocentric ecliptic coordinates

Find the period, P, in days.

P = (365.256898326 days) a¹·⁵

Find the mean anomaly, m, in radians.

m₀ = (t − T) / P
m = 2π [ m₀ − integer(m₀) ]

Find the eccentric anomaly, u, in radians.

The Danby first approximation for the eccentric anomaly, u, in radians.

u' = m
+ (e − e³/8 + e⁵/192) sin(m)
+ (e²/2 − e⁴/6) sin(2m)
+ (3e³/8 − 27e⁵/128) sin(3m)
+ (e⁴/3) sin(4m)

The Danby's method refinement for the eccentric anomaly.

u = u'

REPEAT
U = u
F₀ = U − e sin U − m
F₁ = 1 − e cos U
F₂ = e sin U
F₃ = e cos U
D₁ = −F₀ / F₁
D₂ = −F₀ / [ F₁ + D₁F₂/2 ]
D₃ = −F₀ / [ F₁ + D₁F₂/2 + D₂²F₃/6 ]
u = U + D₃
UNTIL |u−U| is less than 1ᴇ-14

The loop, just above, converges u to the correct value of the eccentric anomaly. Usually. However, when e is near one and the orbiting object is near the periapsis of its orbit, there is a chance that this loop will fail to converge. In such cases, a different root-finding method will be needed.

Find the canonical position vector of the object in its orbit at time t.

x''' = a (cos u − e)
y''' = a sin u √(1−e²)
z''' = 0

Find the true anomaly, θ. We'll use it below when we find the velocity.

θ = arctan( y''' , x''' )

Rotate the triple-prime position vector by the argument of the perihelion, ω.

x'' = x''' cos ω − y''' sin ω
y'' = x''' sin ω + y''' cos ω
z'' = z''' = 0

Rotate the double-prime position vector by the inclination, i.

x' = x''
y' = y'' cos i
z' = y'' sin i

Rotate the single-prime position vector by the longitude of the ascending node, Ω.

x = x' cos Ω − y' sin Ω
y = x' sin Ω + y' cos Ω
z = z'

The unprimed position vector [x,y,z] is the position in heliocentric ecliptic coordinates.

Find the canonical (triple-prime) heliocentric velocity vector.

k = √{ GM / [ a AU (1 − e²) ] }

k is a speed in meters per second.

Vx''' = −k sin θ
Vy''' = k (e + cos θ)
Vz''' = 0

Rotate the triple-prime velocity vector by the argument of the perihelion, ω.

Vx'' = Vx''' cos ω − Vy''' sin ω
Vy'' = Vx''' sin ω + Vy''' cos ω
Vz'' = Vz''' = 0

Rotate the double-prime velocity vector by the inclination, i.

Vx' = Vx''
Vy' = Vy'' cos i
Vz' = Vy'' sin i

Rotate the single-prime velocity vector by the longitude of the ascending node, Ω.

Vx = Vx' cos Ω − Vy' sin Ω
Vy = Vx' sin Ω + Vy' cos Ω
Vz = Vz'

The unprimed velocity vector [Vx,Vy,Vz] is the sun-relative velocity in ecliptic coordinates.

Calculate the position and velocity of the spaceship in its initial orbit at the time of departure

P = 365.257994y'' = +0.979054316Vy''' = +30019.1146
m₀ = 9.97935722x' = −0.092732158Vx'' = −30140.9504
m = 6.15348288y' = +0.979054316Vy'' = −2921.69307
u' = 6.15128508z' = 0Vx' = −30140.9504
u = 6.15128508xi = −0.092732158Vy' = −2921.69307
x''' = +0.974604719yi = +0.979054316Vz' = 0
y''' = −0.131499998zi = 0Vxi = −30140.9504
θ = 6.14906877k = 29788.8217Vyi = −2921.69307
x'' = −0.092732158Vx''' = +3983.20734Vzi = 0


Calculate the position and velocity of Vesta at the time of arrival

P = 1325.30752y'' = +0.651051227Vy''' = +20727.481
m₀ = 3.02910935x' = −2.0545179Vx'' = −6748.92645
m = 0.182899417y' = +0.646009389Vy'' = −20049.7967
u' = 0.200646945z' = +0.080867606Vx' = −6748.92645
u = 0.200648459xf = −0.13298229Vy' = −19894.5281
x''' = +2.10361404yf = −2.14957848Vz' = −2490.40168
y''' = +0.468742457zf = +0.080867606Vxf = +20933.6861
θ = 0.219245394k = 19460.2928Vyf = −1766.64767
x'' = −2.0545179Vx''' = −4232.48025Vzf = −2490.40168


We will refer to a "hypothetical" transfer orbit until we have assured ourselves that it satisfies the condition that the calculated transit time be equal, or very nearly equal, to the required transit time.

The required transit time is the amount of time that the destination object (Vesta, in our example) takes to go from where it is at t₁ to where it is at t₂. This time difference is, of course, t₂−t₁.

The calculated transit time is the amount of time, Δt, that the spaceship takes to travel, along the hypothetical transfer orbit, from where it is at t₁ to the intersection of the hypothetical transfer orbit with the orbit of the destination object.

In general, Δt will differ substantially from t₂−t₁. It is necessary that t₁ and t₂ be chosen such that Δt is nearly equal to t₂−t₁. Once we know that to be the case, we can drop the word "hypothetical," for we will have determined that the transfer orbit does, indeed, exist.


The determination of an elliptical transfer-intercept orbit from a position and time of departure and from a position and time of arrival

At time t₁ a spaceship in free orbit around the sun (i.e. there is no planet nearby) has this state vector:

xi , yi , zi , Vxi , Vyi , Vzi

At time t₂ (such that t₂>t₁) an asteroid in free orbit around the sun (i.e. there is no significant perturbing third mass) has this state vector:

xf , yf , zf , Vxf , Vyf , Vzf

We want to find out whether or not there exists a transfer orbit between the position elements of those two state vectors, such that

x₁ = xi
y₁ = yi
z₁ = zi

x₂ = xf
y₂ = yf
z₂ = zf

The subscript 1 denotes "pertaining to the transfer orbit at transfer orbit insertion" or "departure."

The subscript 2 denotes "pertaining to the transfer orbit at its intersection with the destination object's orbit" or "arrival." (Whether the destination object is actually there at that same time is a question we will answer presently.)

r₁ = √[ x₁² + y₁² + z₁² ]
r₂ = √[ x₂² + y₂² + z₂² ]
d = √[ (x₂−x₁)² + (y₂−y₁)² + (z₂−z₁)² ]

We define the integer variable β and permit it to have only the values 1 and 2.

If β=1, an apside (perihelion or aphelion) of the transfer orbit occurs at departure.
If β=2, an apside (perihelion or aphelion) of the transfer orbit occurs at arrival.

β = either 1 or 2
φ = 3 − β
N = (−1)ᵠ

The variables β and φ will usually be subscripts. The variable N is a sign toggle factor.

m : mean anomaly
u : eccentric anomaly
θ : true anomaly

If the apside at the apsidal endpoint of the intended trajectory is the perihelion, then

mᵦ = uᵦ = θᵦ = 0

If the apside at the apsidal endpoint of the intended trajectory is the aphelion, then

mᵦ = uᵦ = θᵦ = π radians

The eccentricity of a conic section, having the sun at a focus, which includes the point of departure and the point of arrival, is found by solving, simultaneously,

The polar equations which relates the heliocentric distances with the true anomalies,

r₁ = a (1−e²) / (1 + e cos θ₁)
r₂ = a (1−e²) / (1 + e cos θ₂)

The law of cosines,

d² = r₁² + r₂² − 2 r₁ r₂ cos(θ₂−θ₁)

In those equations, the known quantities are d, r₁, r₂, and whichever of the true anomalies, θᵦ, has the hypothetical transfer orbit's apside. The cosine of θᵦ is +1 if that apside is the perihelion, and it is −1 if it is the aphelion. The condition that one of the endpoints of the intended trajectory, either departure or arrival, occurs at one of the apsides of the hypothetical transfer orbit is why you don't need a third point on the transfer orbit to determine its elements. The three equations have three unknown quantities, namely a, e, and θᵩ.

After some algebra, we get the eccentricity of the hypothetical transfer orbit.

e = 2 (cos θᵦ) rᵦ (rᵦ−rᵩ) / (rᵩ² − rᵦ² − d²)

The semimajor axis of the hypothetical transfer orbit is found from

a = rᵦ / (1 − e cos θᵦ)

The true anomaly in the hypothetical transfer orbit at the non-apsidal endpoint of the intended trajectory is found as follows:

θᵩ = θᵦ + N arccos{(rᵦ² + rᵩ² − d²) / (2rᵦrᵩ)}

The eccentric anomaly in the hypothetical transfer orbit at the non-apsidal endpoint of the intended trajectory is found as follows:

sin uᵩ = (rᵩ/a) sin θᵩ / √(1−e²)
cos uᵩ = (rᵩ/a) cos θᵩ + e
uᵩ = arctan(sin uᵩ , cos uᵩ)

The mean anomaly in the hypothetical transfer orbit at the non-apsidal endpoint of the intended trajectory is found as follows:

mᵩ = uᵩ − e sin uᵩ

The period of the hypothetical transfer orbit is

P = (365.256898326 days) a¹·⁵

The mean motion in the hypothetical transfer orbit is

μ = 2π/P

For short path trajectories (for which the arc of true anomaly going from departure to arrival is less than π radians), the calculated transit time in the hypothetical transfer orbit is

Δt = (N/μ) [mᵩ − π sin(θᵦ/2)]

Here's the test that determines whether a transfer orbit exists between heliocentric position r₁ at time t₁ and heliocentric position r₂ at time t₂. It is necessary that

Δt ≈ t₂ − t₁

And the match should be a close one, ideally a small fraction of a second. In general, this will not be the case. If the difference in the required and the calculated transit times is unacceptably large, then the spaceship pilot will have to choose either a different departure time, or a different arrival time, or both, and try again.

The procedure being demonstrated here finds elliptical transfer orbits of the short path, by which it is meant that the arc of true anomaly along the intended trajectory, from departure to arrival, is strictly less than π radians. One of the transfer orbit's apsides will occur at either the position of departure or at the position of arrival, but the other apside will not occur at all within the intended trajectory. To be complete about things, we will calculate the time of perihelion passage in the transfer orbit, whether or not the spaceship is ever there.

T = tᵦ − mᵦ/μ

The inclination of the transfer orbit is found from the cross product of the heliocentric position vectors of departure and arrival, r₁ x r₂.

Xn' = y₁ z₂ − z₁ y₂
Yn' = z₁ x₂ − x₁ z₂
Zn' = x₁ y₂ − y₁ x₂

Rn' = √[ (Xn')² + (Yn')² + (Zn')² ]

Xn = Xn' / Rn'
Yn = Yn' / Rn'
Zn = Zn' / Rn'

The vector Rn is a unit normal to the transfer orbit in the direction of the orbit's angular momentum.

i = arccos(Zn)

Having found the components of the vector normal to the transfer orbit (in the direction of the angular momentum), we now use it to find the velocity in the transfer orbit at the apsidal endpoint of the intended trajectory.

Vxᵦ'' = Yn zᵦ − Zn yᵦ
Vyᵦ'' = Zn xᵦ − Xn zᵦ
Vzᵦ'' = Xn yᵦ − Yn xᵦ

Vᵦ'' = √[ (Vxᵦ'')² + (Vyᵦ'')² + (Vzᵦ'')² ]

Vxᵦ' = Vxᵦ'' / Vᵦ''
Vyᵦ' = Vyᵦ'' / Vᵦ''
Vzᵦ' = Vzᵦ'' / Vᵦ''

Vᵦ = √[ (GM/AU) (2/rᵦ − 1/a) ]

Vxᵦ = Vᵦ Vxᵦ'
Vyᵦ = Vᵦ Vyᵦ'
Vzᵦ = Vᵦ Vzᵦ'

Now we find the angular momentum per unit mass in the transfer orbit.

hx = AU (yᵦ Vzᵦ − zᵦ Vyᵦ)
hy = AU (zᵦ Vxᵦ − xᵦ Vzᵦ)
hz = AU (xᵦ Vyᵦ − yᵦ Vxᵦ)

From here, we find the longitude of the ascending node of the transfer orbit.

Ω = arctan( hx , −hy )

Notice that hx is proportional to sin Ω, while −hy is proportional to cos Ω.

We find the argument of the perihelion of the transfer orbit as follows:

cos ω'' = (xᵦ cos Ω + yᵦ sin Ω) / rᵦ

If sin i = 0 then sin ω'' = (yᵦ cos Ω − xᵦ sin Ω) / rᵦ
If sin i ≠ 0 then sin ω'' = zᵦ / (rᵦ sin i)

ω'' = arctan( sin ω'' , cos ω'' )

ω' = ω'' − θᵦ

If ω' ≥ 0 then ω = ω'
If ω' < 0 then ω = ω' + 2π

The two known points on the hypothetical transfer orbit are

x₁ = −0.092732158 AU
y₁ = +0.979054316 AU
z₁ = 0

x₂ = −0.13298229 AU
y₂ = −2.14957848 AU
z₂ = +0.080867606 AU

The sides of the sun-departure-arrival triangle are

r₁ = 0.98343612 AU
r₂ = 2.15520567 AU
d = 3.129936551 AU

We are given that the apoapsis of the hypothetical transfer orbit occurs at the arrival position, so

β = 2
φ = 1
N = −1
m₂ = u₂ = θ₂ = π radians

The eccentricity and the semimajor axis of the hypothetical transfer orbit are

e = 0.37484849
a = 1.56759505 AU

The true, eccentric, and mean anomalies in the hypothetical transfer orbit at the non-apsidal endpoint of the intended trajectory (i.e. the departure position) are

θ₁ = 0.16062918 radians
u₁ = 0.10844236 radians
m₁ = 0.067872532 radians

The period and mean motion of the hypothetical transfer orbit are

P = 716.884602 days
μ = 0.00876457005 radians/day

The calculated and required transit times in the hypothetical transfer orbit, from departure to arrival, are

Δt = 350.698335 days
t₂−t₁ = 350.69833375 days

Subject to roundoff error, the difference is about one-tenth of a second. That's close enough. The transfer orbit exists.

The time of perihelion passage in the transfer orbit (although the spaceship is never there) is

T = JD 2457923.256033 = 18h 8m 41s UTC on 18 June 2017

Find the unit normal vector to the plane of the transfer orbit

Xn' = +0.079173779
Yn' = +0.0074990276
Zn' = +0.329531936

Rn' = 0.338992654

Xn = +0.233556030
Yn = +0.0221215048
Zn = +0.972091673

The transfer orbit's inclination to the ecliptic

i = 13.56812324°

Find the velocity in the transfer orbit at the apsidal endpoint of the intended trajectory

Vx₂'' = +2.091376254
Vy₂'' = −0.148158093
Vz₂'' = −0.499105248

V₂'' = 2.155205676

Vx₂' = +0.970383605
Vy₂' = −0.068744295
Vz₂' = −0.231581261

V₂ = 16041.367805 m/s

Vx₂ = +15566.280326 m/s
Vy₂ = −1102.752513 m/s
Vz₂ = −3714.880181 m/s

The angular momentum per unit mass

hx = +1.207943483ᴇ15 m²/s
hy = +1.144116363ᴇ14 m²/s
hz = +5.027623568ᴇ15 m²/s

The transfer orbit's longitude of the ascending node

Ω = 95.41068849°

Find the transfer orbit's argument of the perihelion

cos ω'' = −0.987126840
sin ω'' = +0.159939380
ω'' = 2.980963411 radians
ω' = −0.160629243 radians
ω = 350.79662233°

Keplerian elements of the transfer orbit

a = 1.56759505 AU
e = 0.37484849
i = 13.56812324°
Ω = 95.41068849°
ω = 350.79662233°
T = JD 2457923.256033

Now that you have the elements of the transfer orbit, you can calculate the changes-of-velocity needed for transfer orbit insertion (departure) and for matching velocity with the target asteroid at arrival.


When we reduce the elements of the transfer orbit with the time of departure, t₁, we find that the velocity of the spaceship in the transfer orbit is

Vx₁ = −34166.4329 m/s
Vy₁ = −1690.83202 m/s
Vz₁ = +8247.34992 m/s

The velocity of the spaceship in its initial orbit at t₁ was

Vxi = −30140.9504 m/s
Vyi = −2921.69307 m/s
Vzi = 0.0 m/s

So the change of velocity required at departure for transfer orbit insertion is

ΔVx₁ = −4025.4825 m/s
ΔVy₁ = +1230.8611 m/s
ΔVz₁ = +8247.3499 m/s

ΔV₁ = 9259.4983 m/s


The velocity of Vesta, when it is intercepted by the spaceship, is

Vxf = +20933.6861 m/s
Vyf = −1766.64767 m/s
Vzf = −2490.40168 m/s

When we reduce the elements of the transfer orbit with the time of arrival, t₂, we find that the velocity of the spaceship in the transfer orbit is

Vx₂ = +15566.2801 m/s
Vy₂ = −1102.75259 m/s
Vz₂ = −3714.88014 m/s

So the change of velocity required of the spaceship at arrival to match velocity with Vesta is

ΔVx₂ = +5367.4060 m/s
ΔVy₂ = −663.8951 m/s
ΔVz₂ = +1224.4785 m/s

ΔV₂ = 5545.1917 m/s


Remember that all of the unprimed vectors in this tutorial are referred to ecliptic coordinates. If you want them in celestial coordinates (so that you can use a star chart to show you the right ascension and declination in which to point the nose of your spaceship when you apply thrust), you'll still have that to do.


Converting a velocity vector from rectangular ecliptic coordinates to spherical celestial coordinates

Let's convert the departure delta-vee in our example. Here it is in ecliptic coordinates:

ΔVx₁ = −4025.4825 m/s
ΔVy₁ = +1230.8611 m/s
ΔVz₁ = +8247.3499 m/s

The obliquity of the ecliptic, ε, can be estimated from the Laskar equation.

T = (t−2451545) / 3652500

Ɛ = 84381.448″ − 4680.93″ T − 1.55″ T² + 1999.25″ T³ − 51.38″ T⁴
− 249.67″ T⁵ − 39.05″ T⁶ + 7.12″ T⁷ + 27.87″ T⁸ + 5.79″ T⁹ + 2.45″ T¹⁰

ε = Ɛ / 206264.806247

t = t₁ = JD 2457931.0
T = 0.00174839151266
Ɛ = 84373.263907"
ε = 0.409053126623 radians

The magnitude of the vector does not change by the rotation. It remains

ΔV₁' = ΔV₁ = √[ (ΔVx₁)² + (ΔVy₁)² + (ΔVz₁)² ]
ΔV₁' = 9259.4983 m/s

The velocity vector in celestial coordinates is found from

ΔVx₁' = ΔVx₁
ΔVy₁' = ΔVy₁ cos ε − ΔVz₁ sin ε
ΔVz₁' = ΔVy₁ sin ε + ΔVz₁ cos ε

ΔVx₁' = −4025.4825 m/s
ΔVy₁' = −2150.9947 m/s
ΔVz₁' = +8056.4894 m/s

The right ascension of the direction in which the velocity vector points is

α₁ = (12 hours/π) arctan( ΔVy₁' , ΔVx₁' )
α₁ = 13.8745051 hours

The declination of the direction in which the velocity vector points is

δ₁ = (180°/π) arcsin( ΔVz₁' / ΔV₁' )
δ₁ = +60.467750°


A check on the accuracy of the method by a numerical evolution of the state vector

As calculated from the Keplerian elements of the transfer orbit, at time t₁ = JD 2457931.0, the spaceship's heliocentric state vector is

x₁ = −0.092732158 AU
y₁ = +0.979054316 AU
z₁ = 0
Vx₁ = −34166.4329 m/s
Vy₁ = −1690.83202 m/s
Vz₁ = +8247.34992 m/s

As calculated from the Keplerian elements of the transfer orbit, at time t₂ = JD 2458281.69833375, the spaceship's heliocentric state vector is

x₂ = −0.13298229 AU
y₂ = −2.14957848 AU
z₂ = +0.080867606 AU
Vx₂ = +15566.2801 m/s
Vy₂ = −1102.75259 m/s
Vz₂ = −3714.88014 m/s

The transit time of the spaceship in the transfer orbit is
t₂−t₁ = 30300336.036 sec

If we take the state vector at t₁ and numerically walk it forward in time by 1 second intervals for 30300336 seconds, we get this result.

x = −0.132983124 AU
y = −2.149579643 AU
z = +0.080867833 AU
Vx = +15566.27354 m/s
Vy = −1102.76889 m/s
Vz = −3714.87818 m/s
Jenab6

Reply to RamzPaul regarding the real difference between religion and science

Concerning a RamzPaul video:

This is a false portrayal of the dark matter vs modified gravity theory controversy. No scientist is saying that the universe is wrong, as that would be equivalent to saying the the truth is false. Scientists don't know for certain why the stars in the spiral arms of galaxies orbit the center of their galaxy faster than the standard theory of gravity would predict. They are trying to find out what the reason is, and they are reserving final judgment on that reason until enough evidence has become available.

That's how science works. Having to accept uncertainty, learning to live without "absolute" certainty, is a strength that is often misconstrued as a weakness.

The better measure of a purported method for seeking truth, whether it is scientific or religious, is how much it has increased the powers of mankind over time. Valid methods for seeking truth do that because useful truths are a subset of all truths, and it is a subset in which people have a particular interest and to which they devote a considerable amount of their time. Any method for seeking truth that really does work will discover useful truths often, and the powers of men will grow thereby.

Conversely, if all that a purported method for finding truth has ever done is spin unprovable fantasies about a deity and an afterlife, intended to comfort people as they are dying, but which fantasies are in conflict with each other about fundamental issues (e.g. Christian doctrine vs. Muslim doctrine), and they do not discover any useful truths that increase the powers of men, then most likely that method for seeking truth doesn't really work.

The basic difference between science and religion is that science treats truth as something to be discovered, whereas religion treats truth as something to be decided (or revealed by other people who did the deciding). The practical consequence of that difference is that different religious groups will come up with religious metaphysics that disagree with each other on the most fundamental level, whereas science will lead different groups, working independently of each other, to the same conclusions, after enough data has been gathered to identify the hypothesis that is most likely correct.
Jenab6

Science, Philosophy, and Ethics

This is reposted here because it was hidden by Amazon's "sensitivity filter." It will appear also on my VK and LiveJournal blogs, on Gab, and maybe elsewhere as well.
.

I suspect that philosophers know as little, in the absence of science, about ethics than they do about anything else. Rather, the reason philosophers make free, at present, with their ethical pronouncements is the same as the reason the Church made free with its astrodynamical pronouncements in the 17th century. The reason is that science has not yet investigated the subject with rigor.

Philosophy doesn't gather facts about reality within itself, whether we are speaking about physics or about ethics. It is as blind for one as it is for the other. Nobody is privileged to choose what is moral. Nature has its own standard for morality, and that standard is survival. What does not exist is worthless. And an improper moral system that causes its own destruction via that of its practitioners is worse than worthless; like a disease, it has a negative worth.

What philosophy does is concoct logically self-consistent narratives, which might or might not be the truth. Philosophy and science inform each other: philosophy informs science about correct procedure, and science tells philosophy what the discovered facts are and which of its narratives has been disqualified from being truth.

A philosopher who does not engage with science is blind to reality. He forever spins conjectures that he has no way of checking. He gets into arguments with similarly blind other philosophers who insist that their conjectures are superior to his, and none of them really know what the truth is because none of them has indulged in experimental verification. Their arguments are so much hot air.

You know the old saying among atheists: "As science advances, God retreats," meaning that once experiment has revealed the true nature of a part of existence, the older theological explanations quickly seem obsolete — if not outright ridiculous. After three or four hundred years of trying to refute a scientific explanation that is supported at every turn by every test, while at the same time having their increasingly contrived alternatives either disproved or shown to be rather suspiciously untestable, the theologians adopt the scientific explanation, grudgingly at first, but after a generation they are pretending that they had never thought differently.

Ethics is like that. Philosophers may claim to have knowledge about ethics because they believe it to be subject to their choices. Some philosophers may believe that they can create ethics by making their preferences known. On the contrary, I say. Those philosophers are wrong. Nature constrains the truth about ethics to the same degree that it constrains the truth about gravity. This truth is something to discover. It isn't something to be decided.

When you discover the truth about ethics, you might not like it. You might wish that it were something else. But it will be the truth, nevertheless. The approval of the philosophers isn't required.
Jenab6

Half-Lives of Radioactive Isotopes

Half-Lives of Radioactive Isotopes

PT = Planck time unit
PT = √(ћG/c⁵) = 5.391247e-44 sec

1 yoctosecond = 1e-24 sec = 1.85485844e+19 PT

hydrogen-7, 23e-24 sec
lithium-4, 75.6e-24 sec
hydrogen-5, 80e-24 sec
hydrogen-4, 139e-24 sec
nitrogen-10, 200e-24 sec
hydrogen-6, 290e-24 sec
lithium-5, 304e-24 sec
boron-7, 350e-24 sec
fluorine-15, 460e-24 sec
nitrogen-11, 590e-24 sec
nitrogen-11m, 690e-24 sec
helium-5, 760e-24 sec

1 zeptosecond = 1e-21 sec = 1.85485844e+22 PT

oxygen-12, 1.14e-21 sec
sodium-18, 1.34e-21 sec
helium-10, 1.52e-21 sec
lithium-10, 2e-21 sec
carbon-8, 2e-21 sec
beryllium-13, 2.7e-21 sec
helium-7, 3.040e-21 sec
neon-16, 3.74e-21 sec
beryllium-6, 5e-21 sec
helium-9, 7e-21 sec
fluorine-16, 11e-21 sec
boron-9, 845e-21 sec

1 attosecond = 1e-18 sec = 1.85485844e+25 PT

beryllium-8, 81.9e-18 sec

1 femtosecond = 1e-15 sec = 1.85485844e+28 PT

oxygen-27, 1.75e-15 sec

1 picosecond = 1e-12 sec = 1 psec = 1.85485844e+31 PT

boron-16, ≤190e-12 sec

1 nanosecond = 1e-9 sec = 1 nsec = 1.85485844e+34 PT

lithium-12, <10e-9 sec
boron-18, 26e-9 sec
carbon-21, 30e-9 sec
fluorine-28, 40e-9 sec
oxygen-26, 40e-9 sec
sodium-19, 40e-9 sec
oxygen-25, 50e-9 sec
nitrogen-24, 52e-9 sec
protactinium-219, 53e-9 sec
neon-34, 60e-9 sec
sodium-37, 60e-9 sec
protactinium-220m2, 69e-9 sec
actinium-217, 69e-9 sec
uranium-236m1, 100e-9 sec
oxygen-28, 100e-9 sec
curium-247m2, 100.6e-9 sec
actinium-218m, 103e-9 sec
thorium-218, 109e-9 sec
neptunium-238m, 112e-9 sec
uranium-236m2, 120e-9 sec
americium-239m, 163e-9 sec
neon-33, 180e-9 sec
sodium-36, 180e-9 sec
curium-242m, 180e-9 sec
radium-216, 182e-9 sec
plutonium-239m1, 193e-9 sec
beryllium-15, 200e-9 sec
beryllium-16, 200e-9 sec
fluorine-31, 250e-9 sec
uranium-239m1, >250e-9 sec
fluorine-30, 260e-9 sec
nitrogen-25, 260e-9 sec
radium-208m, 270e-9 sec
uranium-238m, 280e-9 sec
curium-245m, 290e-9 sec
polonium-212, 299e-9 sec
protactinium-220m1, 308e-9 sec
plutonium-243m, 330e-9 sec
neptunium-222, 380e-9 sec
protactinium-229m, 420e-9 sec
curium-244m2, >500e-9 sec
radium-215m3, 555e-9 sec
berkelium-242m, 600e-9 sec
thorium-216m2, 615e-9 sec
uranium-221, 660e-9 sec
actinium-217m, 740e-9 sec
protactinium-220, 780e-9 sec
uranium-239m2, 780e-9 sec
radium-212m2, 850e-9 sec
plutonium-241m1, 880e-9 sec

1 microsecond = 0.000001 sec = 1e-6 sec = 1 μsec = 1.85485844e+37 PT

thorium-219, 1.05e-6 sec
curium-243m, 1.08e-6 sec
actinium-218, 1.08e-6 sec
plutonium-237m2, 1.1e-6 sec
americium-241m, 1.2e-6 sec
radium-215m2, 1.39e-6 sec
uranium-222, 1.4e-6 sec
radium-217, 1.63e-6 sec
neptunium-223, 2.15e-6 sec
radium-210m, 2.24e-6 sec
protactinium-221, 4.9e-6 sec
nobelium-250, 5.7e-6 sec
thorium-229m, 7e-6 sec
radium-215m1, 7.1e-6 sec
plutonium-239m2, 7.5e-6 sec
thorium-220, 9.7e-6 sec
radium-212m1, 10.9e-6 sec
actinium-219, 11.8e-6 sec
uranium-223, 21e-6 sec
plutonium-241m2, 21e-6 sec
fermium-251m, 21.1e-6 sec
curium-249m, 23e-6 sec
rutherfordium-254, 23e-6 sec
neptunium-220, 25e-6 sec
radium-218, 25.2e-6 sec
curium-247m1, 26.3e-6 sec
berkelium-250m1, 29e-6 sec
nobelium-253m, 31e-6 sec
americium-238m, 35e-6 sec
nobelium-250m, 36e-6 sec
neptunium-224, 38e-6 sec
californium-249m, 45e-6 sec
rutherfordium-253, 48e-6 sec
radium-231m, ~53e-6 sec
uranium-219, 55e-6 sec
berkelium-251m, 58e-6 sec
americium-246m2, 73e-6 sec
seaborgium-261m, 92e-6 sec
protactinium-218, 113e-6 sec
thorium-216m1, 137e-6 sec
curium-248m, 146e-6 sec
neptunium-219, 150e-6 sec
polonium-214, 164e-6 sec
darmstadtium-270, 205e-6 sec
berkelium-250m2, 213e-6 sec
darmstadtium-269, 230e-6 sec
copernicium-277, 240e-6 sec
thorium-217, 240e-6 sec
darmstadtium-273, 240e-6 sec
berkelium-249m, 300e-6 sec
nihonium-278, 340e-6 sec
hassium-265m, 360e-6 sec
fermium-258, 370e-6 sec
actinium-216, 440e-6 sec
actinium-216m, 443e-6 sec
hassium-264, 540e-6 sec
copernicium-277, 690e-6 sec
oganesson-294, 690e-6 sec
fermium-241, 730e-6 sec
hassium-263, 760e-6 sec
fermium-242, 800e-6 sec
mendelevium-245, 900e-6 sec
copernicium-282, 910e-6 sec
uranium-224, 940e-6 sec

1 millisecond = 0.001 sec = 1e-3 sec = 1 msec = 1.85485844e+40 PT

protactinium-217m, 1.08e-3 sec
meitnerium-266, 1.2e-3 sec
nobelium-258, 1.2e-3 sec
uranium-216m, 1.31e-3 sec
nihonium-278, 1.4e-3 sec
sodium-35, 1.5e-3 sec
darmstadtium-271m, 1.7e-3 sec
thorium-208, 1.7e-3 sec
thorium-221, 1.73e-3 sec
hassium-265, 1.96e-3 sec
roentgenium-272, 2e-3 sec
thorium-222, 2.237e-3 sec
uranium-215, 2.24e-3 sec
fluorine-29, 2.5e-3 sec
flerovium-284, 2.5e-3 sec
boron-19, 2.92e-3 sec
seaborgium-258, 3e-3 sec
hassium-266, 3.02e-3 sec
fermium-244, 3.12e-3 sec
protactinium-222, 3.2e-3 sec
neon-31, 3.4e-3 sec
protactinium-217, 3.48e-3 sec
neon-32, 3.5e-3 sec
darmstadtium-277, 3.5e-3 sec
protactinium-211, 3.8e-3 sec
roentgenium-278, 4e-3 sec
seaborgium-260, 4e-3 sec
uranium-216, 4.3e-3 sec
beryllium-14, 4.35e-3 sec
meitnerium-278, 4.5e-3 sec
radon-196, 4.7e-3 sec
fluorine-27, 5e-3 sec
meitnerium-277, 5e-3 sec
nobelium-262, 5e-3 sec
boron-17, 5.08e-3 sec
protactinium-223, 5.1e-3 sec
americium-223, 5.2e-3 sec
sodium-34, 5.5e-3 sec
neptunium-225, 6e-3 sec
uranium-218, 6e-3 sec
carbon-22, 6.2e-3 sec
meitnerium-270, 6.3e-3 sec
rutherfordium-256, 6.4e-3 sec
thorium-209, 7e-3 sec
protactinium-213, 7e-3 sec
seaborgium-262, 7e-3 sec
neon-30, 7.3e-3 sec
protactinium-212, 8e-3 sec
sodium-33, 8e-3 sec
livermorium-290, 8.3e-3 sec
oxygen-13, 8.58e-3 sec
lithium-11, 8.59e-3 sec
fluorine-26, 9.6e-3 sec
bohrium-262m, 9.6e-3 sec
boron-15, 9.87e-3 sec
darmstadtium-270m, 10e-3 sec
hassium-277, 11e-3 sec
nitrogen-12, 11e-3 sec
bohrium-261, 11.8e-3 sec
roentgenium-274, 12e-3 sec
boron-14, 12.5e-3 sec
livermorium-292, 13e-3 sec
sodium-32, 13.2e-3 sec
americium-242m2, 14.0e-3 sec
protactinium-215, 14e-3 sec
nitrogen-23, 14.5e-3 sec
rutherfordium-258, 14.7e-3 sec
neon-29, 14.8e-3 sec
actinium-206m1, 15e-3 sec
carbon-20, 16e-3 sec
protactinium-214, 17e-3 sec
sodium-31, 17e-3 sec
thorium-210, 17e-3 sec
boron-13, 17.33e-3 sec
neon-28, 18.9e-3 sec
livermorium-291, 19e-3 sec
actinium-205, 20e-3 sec
rutherfordium-270, 20e-3 sec
meitnerium-275, 20e-3 sec
boron-12, 20.2e-3 sec
rutherfordium-260, 21e-3 sec
californium-238, 21.1e-3 sec
beryllium-12, 21.49e-3 sec
tennessine-293, 22e-3 sec
nitrogen-22, 24e-3 sec
actinium-206, 25e-3 sec
uranium-217, 26e-3 sec
actinium-220, 26.36e-3 sec
thorium-216, 26.8e-3 sec
meitnerium-268, 27e-3 sec
lawrencium-251, 27e-3 sec
actinium-208m, 28e-3 sec
sodium-28, 30.5e-3 sec
actinium-207, 31e-3 sec
neon-27, 32e-3 sec
uranium-234m, 33.5e-3 sec
curium-244m1, 34e-3 sec
bohrium-260, 35e-3 sec
neptunium-226, 35e-3 sec
thorium-212, 36e-3 sec
moscovium-287, 37e-3 sec
seaborgium-264, 37e-3 sec
dubnium-255, 37e-3 sec
actinium-206m2, 41e-3 sec
sodium-29, 44.9e-3 sec
carbon-19, 46.2e-3 sec
thorium-211, 48e-3 sec
sodium-30, 48.4e-3 sec
fluorine-25, 50e-3 sec
tennessine-294, 51e-3 sec
actinium-221, 52e-3 sec
hassium-267, 55e-3 sec
livermorium-293, 57e-3 sec
uranium-225, 61e-3 sec
oxygen-24, 65e-3 sec
nihonium-282, 73e-3 sec
nihonium-283, 75e-3 sec
oxygen-23, 82e-3 sec
bohrium-262, 84e-3 sec
nitrogen-21, 87e-3 sec
darmstadtium-271, 90e-3 sec
roentgenium-279, 90e-3 sec
carbon-18, 92e-3 sec
actinium-209, 92e-3 sec
actinium-208, 97e-3 sec
copernicium-284, 98e-3 sec
thorium-214, 100e-3 sec
flerovium-285, 100e-3 sec
protactinium-216, 105e-3 sec
nobelium-260, 106e-3 sec
helium-8, 119e-3 sec
flerovium-286, 120e-3 sec
seaborgium-263m, 120e-3 sec
carbon-9, 126.5e-3 sec
nitrogen-20, 130e-3 sec
thorium-213, 140e-3 sec
moscovium-288, 164e-3 sec
actinium-215, 170e-3 sec
lithium-9, 178.3e-3 sec
copernicium-281, 180e-3 sec
plutonium-237m1, 180e-3 sec
neon-26, 192e-3 sec
carbon-17, 193e-3 sec
mendelevium-247m, 200e-3 sec
seaborgium-261, 200e-3 sec
darmstadtium-279, 210e-3 sec
actinium-211, 213e-3 sec
fermium-243, 231e-3 sec
uranium-226, 269e-3 sec
nitrogen-19, 271e-3 sec
hassium-266m, 280e-3 sec
nobelium-254m, 280e-3 sec
hassium-275, 290e-3 sec
sodium-27, 301e-3 sec
moscovium-289, 330e-3 sec
actinium-210, 350e-3 sec
seaborgium-266, 360e-3 sec
fluorine-24, 390e-3 sec
lawrencium-252, 390e-3 sec
mendelevium-245m, 400e-3 sec
mendelevium-244, 400e-3 sec
meitnerium-274, 440e-3 sec
sodium-20, 447.9e-3 sec
meitnerium-276, 450e-3 sec
flerovium-287, 480e-3 sec
hassium-273, 510e-3 sec
neptunium-227, 510e-3 sec
dubnium-259, 510e-3 sec
lawrencium-253, 580e-3 sec
thorium-223, 600e-3 sec
seaborgium-259, 600e-3 sec
neon-25, 602e-3 sec
nitrogen-18, 622e-3 sec
lawrencium-257, 646e-3 sec
moscovium-290, 650e-3 sec
flerovium-288, 660e-3 sec
dubnium-257m, 670e-3 sec
actinium-213, 731e-3 sec
carbon-16, 747e-3 sec
boron-8, 770e-3 sec
nobelium-251, 780e-3 sec
helium-6, 806.7e-3 sec
lithium-8, 839.9e-3 sec
protactinium-224, 844e-3 sec
bohrium-265, 900e-3 sec
bohrium-266, 900e-3 sec
lutetium-153, 900e-3 sec
nihonium-284, 910e-3 sec
actinium-212, 920e-3 sec
bohrium-264, 970e-3 sec

1 second = 1.85485844e+43 PT

seaborgium-263, 1 sec
mendelevium-246, 1.0 sec
thorium-224, 1.05 sec
sodium-26, 1.077 sec
plutonium-228, 1.1 sec
mendelevium-247, 1.12 sec
curium-246m, 1.12 sec
bohrium-271, 1.2 sec
thorium-215, 1.2 sec
rutherfordium-268, 1.4 sec
hassium-268, 1.42 sec
lawrencium-253m, 1.5 sec
fermium-259, 1.5 sec
dubnium-260, 1.52 sec
dubnium-257, 1.53 sec
fermium-246, 1.54 sec
neon-18, 1.672 sec
nobelium-251m, 1.7 sec
protactinium-225, 1.7 sec
americium-229, 1.8 sec
flerovium-289, 1.9 sec
dubnium-256, 1.9 sec
mendelevium-249m, 1.9 sec
dubnium-258m, 1.9 sec
fermium-250m, 1.92 sec
californium-237, 2.1 sec
fluorine-23, 2.23 sec
oxygen-22, 2.25 sec
nobelium-252, 2.27 sec
rutherfordium-255, 2.3 sec
rutherfordium-262, 2.3 sec
carbon-15, 2.449 sec
rutherfordium-259m, 2.5 sec
flerovium-289, 2.6 sec
nobelium-256, 2.91 sec
rutherfordium-259, 3.2 sec
oxygen-21, 3.42 sec
rutherfordium-261m, 4 sec
rutherfordium-257m, 4.1 sec
lawrencium-258, 4.1 sec
fluorine-21, 4.158 sec
nitrogen-17, 4.173 sec
copernicium-283, 4.2 sec
nihonium-285, 4.2 sec
fermium-245, 4.2 sec
fluorine-22, 4.23 sec
meitnerium-278, 4.5 sec
dubnium-258, 4.5 sec
dubnium-261, 4.5 sec
roentgenium-280, 4.6 sec
rutherfordium-257, 4.7 sec
actinium-222, 5.0 sec
einsteinium-240, 6 sec
lawrencium-259, 6.2 sec
mendelevium-248, 7 sec
nitrogen-16, 7.13 sec
seaborgium-265, 8 sec
actinium-214, 8.2 sec
hassium-270, 9 sec
nihonium-286, 9.5 sec
bohrium-272, 9.8 sec
hassium-271, 10 sec
einsteinium-241, 10 sec
fluorine-20, 11.07 sec
darmstadtium-281, 12.7 sec
lawrencium-254, 13 sec
einsteinium-242, 13.5 sec
oxygen-20, 13.51 sec
beryllium-11, 13.81 sec
hassium-269, 16 sec
seaborgium-265m, 16.2 sec
bohrium-267, 17 sec
roentgenium-281, 17 sec
neon-19, 17.22 sec
berkelium-234, 19 sec
carbon-10, 19.29 sec
einsteinium-243, 21 sec
berkelium-233, 21 sec
berkelium-236, 22 sec
lawrencium-255, 22 sec
sodium-21, 22.49 sec
rutherfordium-266, 23 sec
mendelevium-249, 24 sec
nobelium-257, 25 sec
oxygen-19, 26.464 sec
curium-233, 27 sec
lawrencium-256, 27 sec
copernicium-285, 28 sec
dubnium-263, 29 sec
fermium-247, 31 sec
americium-230, 32 sec
dubnium-262, 35 sec
fermium-248, 35.1 sec
einsteinium-244, 37 sec
neon-23, 37.24 sec
bohrium-274, 40 sec
actinium-234, 44 sec
nobelium-254, 51 sec
curium-234, 52 sec
mendelevium-250, 52 sec
sodium-25, 59.1 sec

1 minute = 60 sec = 1.11291506e+45 PT

californium-239, 60 sec
actinium-235, 60 sec
bohrium-270, 61 sec
neptunium-228, 61.4 sec
actinium-222m, 63 sec
californium-240, 64 sec
fluorine-17, 64.49 sec
rutherfordium-263, 66 sec
uranium-227, 66 sec
einsteinium-245, 66 sec
protactinium-234m, 70 sec
oxygen-14, 70.62 sec
actinium-236, 72 sec
rutherfordium-261, 78 sec
americium-232, 79 sec
seaborgium-267, 84 sec
fermium-249, 96 sec
nobelium-253, 97 sec
roentgenium-282, 100 sec
plutonium-230, 102 sec
protactinium-226, 110 sec
berkelium-252, 110 sec
neptunium-243, 111 sec
actinium-232, 119 sec
protactinium-240, 120 sec
plutonium-229, 120 sec
actinium-230, 122 sec
oxygen-15, 122.24 sec
actinium-223, 126 sec
neptunium-242, 130 sec
protactinium-238, 136 sec
neptunium-244, 137 sec
mendelevium-252, 138 sec
americium-234, 139 sec
seaborgium-271, 140 sec
berkelium-238, 144 sec
actinium-233, 145 sec
lawrencium-260, 160 sec
nobelium-255, 190 sec
americium-233, 190 sec
neon-24, 203 sec
californium-242, 209 sec
americium-236, 220 sec
californium-241, 227 sec
mendelevium-251, 240 sec
neptunium-229, 240 sec
einsteinium-247, 273 sec
berkelium-241, 280 sec
neptunium-230, 280 sec
berkelium-240, 290 sec
thorium-237, 290 sec
curium-235, 300 sec
neptunium-242m, 330 sec
curium-236, 410 sec
berkelium-242, 420 sec
thorium-235, 430 sec
neptunium-240m, 433 sec
actinium-231, 450 sec
einsteinium-246, 460 sec
plutonium-231, 520 sec
protactinium-237, 520 sec
thorium-225, 523 sec
protactinium-236, 550 sec
uranium-228, 550 sec
thorium-238, 560 sec
copper-62, 580.4 sec
americium-235, 590 sec
nitrogen-13, 597.9 sec
berkelium-253, 600 sec
mercury-210, 600 sec
mendelevium-254, 600 sec
californium-243, 640 sec
mendelevium-253, 720 sec
californium-256, 740 sec
neptunium-241, 830 sec
seaborgium-269, 840 sec
free neutron, 881.5 sec
neptunium-232, 880 sec
rutherfordium-263, 900 sec

1 kilosecond = 1 ksec = 1000 sec = 1e+3 sec = 1.85485844e+46 PT

curium-251, 1.01e+3 sec
uranium-242, 1.01e+3 sec
californium-244, 1.16e+3 sec
curium-237, 1.2e+3 sec
carbon-11, 1.2200e+3 sec
plutonium-233, 1.25e+3 sec
thorium-233, 1.310e+3 sec
americium-247, 1.38e+3 sec
uranium-239, 1.407e+3 sec
protactinium-235, 1.466e+3 sec
americium-246m1, 1.50e+3 sec
plutonium-235, 1.52e+3 sec
einsteinium-256, 1.52e+3 sec
americium-244m, 1.6e+3 sec
uranium-235m, 1.6e+3 sec
mendelevium-255, 1.6e+3 sec
einsteinium-248, 1.6e+3 sec
mendelevium-254m, 1.7e+3 sec
fermium-250, 1.82e+3 sec
thorium-226, 1.834e+3 sec
plutonium-232, 2.02e+3 sec
neptunium-233, 2.17e+3 sec
thorium-236, 2.25e+3 sec
protactinium-227, 2.30e+3 sec
americium-246, 2.3e+3 sec
lawrencium-261, 2.6e+3 sec
californium-245, 2.70e+3 sec
neptunium-231, 2.93e+3 sec
berkelium-251, 3.34e+3 sec
mendelevium-258m, 3.42e+3 sec
uranium-229, 3.5e+3 sec
nobelium-259, 3.5e+3 sec

1 hour = 1 h = 3600 sec = 6.67749038e+46 PT

dubnium-270, 3.6e+3 sec
neptunium-240, 3.72e+3 sec
actinium-229, 3.76e+3 sec
curium-249, 3.849e+3 sec
gallium-68, 4.063e+3 sec
americium-237, 4.4e+3 sec
mendelevium-256, 4.62e+3 sec
rutherfordium-267, 4.7e+3 sec
dubnium-266, 4.8e+3 sec
californium-255, 5.10e+3 sec
mendelevium-259, 5.8e+3 sec
americium-238, 5.9e+3 sec
einsteinium-249, 6.13e+3 sec
protactinium-239, 6.5e+3 sec
fluorine-18, 6.586e+3 sec
americium-245, 7.4e+3 sec
einsteinium-250m, 8.0e+3 sec
curium-238, 8.6e+3 sec
curium-239, 9.0e+3 sec
fermium-256, 9.46e+3 sec
actinium-224, 10.0e+3 sec
californium-247, 11.2e+3 sec
berkelium-250, 11.56e+3 sec
fermium-254, 11.66e+3 sec
lawrencium-262, 13e+3 sec
berkelium-244, 15.7e+3 sec
berkelium-243, 16e+3 sec
dubnium-267, 17e+3 sec
plutonium-243, 17.84e+3 sec
fermium-251, 19.1e+3 sec
mendelevium-257, 19.9e+3 sec
actinium-228, 22.1e+3 sec
protactinium-234, 24.1e+3 sec
einsteinium-256m, 27e+3 sec
einsteinium-250, 31e+3 sec
plutonium-234, 32e+3 sec
americium-244, 36e+3 sec
erbium-165, 37.3e+3 sec
plutonium-245, 38e+3 sec
lawrencium-266, 40e+3 sec
americium-239, 43e+3 sec
uranium-240, 51e+3 sec
sodium-24, 53.9e+3 sec
americium-242, 57.7e+3 sec
fermium-255, 72.3e+3 sec
protactinium-228, 79e+3 sec
neptunium-236m, 81e+3 sec
berkelium-248m, 85e+3 sec

1 (mean solar) day = 1 d = 86400 sec = 1.60259769e+48 PT

fermium-252, 91.4e+3 sec
thorium-231, 91.88e+3 sec
dubnium-268, 110.9e+3 sec
erbium-160, 102.9e+3 sec
actinium-226, 105.74e+3 sec
protactinium-232, 113e+3 sec
einsteinium-251, 118.8e+3 sec
californium-246, 128.52e+3 sec
protactinium-229, 130e+3 sec
einsteinium-255, 141.48e+3 sec
berkelium-246, 156e+3 sec
neptunium-238, 182.9e+3 sec
americium-240, 182.9e+3 sec
plutonium-247, 196e+3 sec
neptunium-239, 203.6e+3 sec
gold-198, 232.8e+3 sec
fermium-253, 259e+3 sec
gold-199, 273.8e+3 sec
radon-222, 330.35e+3 sec
uranium-231, 360e+3 sec
neptunium-234, 380e+3 sec
calcium-47, 391.9e+3 sec
berkelium-245, 427e+3 sec
manganese-52, 483.1e+3 sec
gold-196, 534.2e+3 sec
uranium-237, 583e+3 sec

1 week = 604800 sec = 1.12181838e+49 PT

einsteinium-257, 670e+3 sec
iodine-131, 693e+3 sec
thulium-167, 799e+3 sec
actinium-225, 860e+3 sec
plutonium-246, 937e+3 sec

1 megasecond = 1 Msec = 1,000,000 sec = 1e+6 sec = 1.85485844e+49 PT

phosphorus-32, 1.235e+6 sec
vanadium-48, 1.38011e+6 sec
protactinium-230, 1.50e+6 sec
californium-253, 1.539e+6 sec
thorium-227, 1.614e+6 sec
einsteinium-253, 1.769e+6 sec
uranium-230, 1.80e+6 sec
thorium-234, 2.082e+6 sec
protactinium-233, 2.3306e+6 sec
curium-240, 2.3e+6 sec
chromium-51, 2.39350e+6 sec
mendelevium-260, 2.40e+6 sec
curium-241, 2.83e+6 sec
einsteinium-255, 3.44e+6 sec
plutonium-237, 3.91e+6 sec
mendelevium-258, 4.45e+6 sec
beryllium-7, 4.590e+6 sec
californium-254, 5.23e+6 sec
cobalt-56, 6.676e+6 sec
scandium-46, 7.239e+6 sec
sulfur-35, 7.544e+6 sec
thulium-168, 8.04e+6 sec
fermium-257, 8.68e+6 sec
thulium-170, 11.11e+6 sec
polonium-210, 11.9e+6 sec
calcium-45, 14.06e+6 sec
curium-242, 14.07e+6 sec
gold-195, 16.08e+6 sec
zinc-65, 21.06e+6 sec
cobalt-57, 23.483e+6 sec
einsteinium-254, 23.82e+6 sec
vanadium-49, 29e+6 sec
berkelium-249, 29e+6 sec
californium-248, 28.81e+6 sec

1 (Julian) year = 1 y = 31,557,600 sec = 5.85348807e+50 PT

ruthenium-106, 32.3e+6 sec
neptunium-235, 34.22e+6 sec
cadmium-109, 40.0e+6 sec
einsteinium-252, 40.76e+6 sec
thorium-228, 60.33e+6 sec
thulium-171, 61e+6 sec
caesium-134, 65.17e+6 sec
sodium-22, 82.1e+6 sec
californium-252, 83.5e+6 sec
iron-55, 87.0e+6 sec
plutonium-236, 90.2e+6 sec
rhodium-101, 100e+6 sec
cobalt-60, 166.35e+6 sec
krypton-85, 339.4e+6 sec
hydrogen-3, 389e+6 sec
californium-250, 413e+6 sec
plutonium-241, 451.0e+6 sec
niobium-93m, 509e+6 sec
curium-244, 571e+6 sec
actinium-227, 687.1e+6 sec
strontium-90, 909e+6 sec
curium-243, 920e+6 sec
caesium-137, 952e+6 sec

1 gigasecond = 1 Gsec = 1e+9 sec = 1.85485844e+52 PT

titanium-44, 2.0e+9 sec
uranium-232, 2.17e+9 sec
plutonium-238, 2.77e+9 sec
samarium-151, 3.05e+9 sec
nickel-63, 3.16e+9 sec
americium-242m1, 4.4e+9 sec
silicon-32, 5.4e+9 sec
argon-39, 8.5e+9 sec
berkelium-248, >9.5e+9 sec
californium-249, 11.1e+9 sec
silver-108m, 13.2e+9 sec
americium-241, 13.64e+9 sec
mercury-194, 14.0e+9 sec
niobium-91, 21e+9 sec
californium-251, 28e+9 sec
holmium-166m1, 38e+9 sec
berkelium-247, 44e+9 sec
radium-226, 50e+9 sec
molybdenum-93, 130e+9 sec
holmium-163, 144e+9 sec
curium-246, 150e+9 sec
carbon-14, 181e+9 sec
plutonium-240, 207.0e+9 sec
thorium-229, 232e+9 sec
americium-243, 233e+9 sec
curium-250, 260e+9 sec
curium-245, 270e+9 sec
niobium-94, 640e+9 sec
plutonium-239, 761e+9 sec

1 terasecond = 1 Tsec = 1e+12 sec = 1.85485844e+55 PT

protactinium-231, 1.034e+12 sec
lead-202, 1.66e+12 sec
lanthanum-137, 1.9e+12 sec
thorium-230, 2.379e+12 sec
nickel-59, 2.4e+12 sec
calcium-41, 3.3e+12 sec
neptunium-236, 4.9e+12 sec
uranium-233, 5.02e+12 sec
rhenium-186m, 6.3e+12 sec
technetium-99, 6.66e+12 sec
krypton-81, 7.2e+12 sec
tin-126, 7.3e+12 sec
uranium-234, 7.75e+12 sec
chlorine-36, 9.5e+12 sec
curium-248, 11.0e+12 sec
bismuth-208, 11.6e+12 sec
plutonium-242, 11.8e+12 sec
aluminium-26, 22.6e+12 sec
selenium-79, 36e+12 sec
beryllium-10, 48e+12 sec
zirconium-93, 48e+12 sec
gadolinium-150, 56e+12 sec
neptunium-237, 67.7e+12 sec
caesium-135, 73e+12 sec
iron-60, 82e+12 sec
technetium-97, 82e+12 sec
dysprosium-154, 95e+12 sec
bismuth-210m, 96e+12 sec
manganese-53, 120e+12 sec
technetium-98, 130e+12 sec
palladium-107, 210e+12 sec
hafnium-182, 280e+12 sec
lead-205, 550e+12 sec
curium-247, 490e+12 sec
iodine-129, 500e+12 sec
uranium-236, 739e+12 sec

1 petasecond = 1 Psec = 1e+15 sec = 1.85485844e+58 PT

niobium-92, 1.10e+15 sec
samarium-146, 2.1e+15 sec
plutonium-244, 2.5e+15 sec
uranium-235, 22.2e+15 sec
potassium-40, 40.3e+15 sec
uranium-238, 141.0e+15 sec
thorium-232, 443e+15 sec

Current age of the universe = 4.345e+17 sec = 8.060e+60 PT

exasecond = 1e+18 sec = 1.85485844e+61 PT

lutetium-176, 1.21e+18 sec
rhenium-187, 1.3002e+18 sec
rubidium-87, 1.554e+18 sec
lanthanum-138, 3.2e+18 sec
samarium-147, 3.3e+18 sec
platinum-190, 20.51e+18 sec

zettasecond = 1e+21 sec = 1.85485844e+64 PT

gadolinium-152, 3.4e+21 sec
indium-115, 13.9e+21 sec
hafnium-174, 63e+21 sec
osmium-186, 63e+21 sec
neodymium-144, 72e+21 sec
samarium-148, 220e+21 sec
cadmium-113, 240e+21 sec

yottasecond = 1e+24 sec = 1.85485844e+67 PT

vanadium-50, 4.4±1.3 e+24 sec
tungsten-180, 56.8±6.3 e+24 sec
europium-151, 160e+24 sec
neodymium-150, 210e+24 sec
molybdenum-100, 270e+24 sec
bismuth-209, 600±63 e+24 sec
zirconium-96, 630e+24 sec
cadmium-116, 980±130 e+24 sec

1e+27 seconds = 1.85485844e+70 PT

calcium-48, 1.4e+27 sec
selenium-82, 3.1e+27 sec
tellurium-130, 25e+27 sec
barium-130, 50e+27 sec
germanium-76, 57e+27 sec
xenon-136, 75e+27 sec
krypton-78, 290e+27 sec
xenon-124, 570e+27 sec

1e+30 seconds = 1.85485844e+73 PT

tellurium-128, 69.4±9.5 e+30 sec

Reference: Wikipedia, https://en.wikipedia.org/wiki/List_of_radioactive_nuclides_by_half-life
Jenab6

The Shooting of Jacob Blake: the Police Are Right, the Blacks Are Lying

On 23 August 2020, in Kenosha, Wisconsin, a male black named Jacob Blake, age 29, attacked police officers with a knife. In response, the police first tased him twice, but the tasers didn't work. Then, in self-defense, the officers shot (but didn't kill) Blake.

The police were responding to a 911 call from a woman who said that her boyfriend, Jacob Blake, had been violent to her and had stolen her car keys. The police identified Blake as someone who was additionally wanted for sexual assault, for trespassing, and for domestic abuse.

When the police arrived, the woman who had called them told the police that Blake had kidnapped her child and was trying to steal her car.

Blake approached the police, concealing the knife as best as he could, and he refused to drop the knife when the police did see it.

The police tried to use non-lethal means (tasers) to subdue Blake, but they didn't work.

Blake attacked police, briefly holding one of the officers in a headlock.

After the police shot Blake, all the blacks began saying that the shooting was "unnecessary," that the account of the police was a big bunch of lies, and that the police were the "real" aggressors. Blake's family hired Ben Crump, the sleazy black attorney who represented the families of black thugs Trayvon Martin and Michael Brown, to represent them in their civil suit against the police, in the hope of winning what has been called a "black payday."

And the blacks in Kenosha rioted, of course. The behavior pattern is well-studied: the blacks first announce that they will assemble to protest peaceably, then, after enough of them have gathered, they become a violent threat to persons and to property, beating and killing law-abiding citizens, breaking car windows, setting fire to businesses, and stealing everything that they can lay their hands on.

Sympathetic (and similar) black protests-cum-riots were held in New York, Minneapolis, Los Angeles, and Atlanta.

Although at first the involved officers were placed on administrative leave (26 August), while the wimpy, pandering Wisconsin Governor Tony Evers denounced excessive use of force by police, the prosecutors eventually (January 2021) decided not to charge them with any criminal offense. Probably because they couldn't make any such charge seem even remotely plausible, given the circumstances.

https://www.startribune.com/no-charges-against-wisconsin-officer-who-shot-jacob-blake/600006905/
Jenab6

Joe Biden, the CCP, and the Water at the Moon's South Pole

There are many reasons for why China would want to control the US government just now. One of them is getting the ability to sabotage the American economy by enforcing unnecessary and unwise lockdowns pertaining to covid. But although that's probably the biggest reason, it isn't the only one.

A race is on to establish defacto ownership, or "stake a claim," on the water ice located at the moon's south pole. The first country to build a lunar colony there will get dibs on all the best lunar water resources. If that country is China, then the future endeavors of the United States on the moon will forever be overshadowed by Chinese control of most of the moon's native water.

And that's another reason for China to support the Democratic Party's frauds in the 2020 election. By cheating Joe Biden, who is beholden to China and possibly subject to blackmail by the CCP, into the White House, the Chinese communists can delay NASA from building a moonbase until China has one first.

The Chinese are very long-range planners.
Jenab6

One of My Golden Oldies

Why do white liberals speak for black people?

Because the liberal whites are better-spoken, meaning they have superior language skills, as compared with the blacks themselves. And the liberal whites are cleverer liars than the blacks are. That’s not to say that blacks aren’t frequently liars. But blacks aren’t especially skilled in making their deceptions convincing.

Blacks make mistakes when they lie, and then they have to resort to intimidation, violence, and dogged persistence and repetition (chanting in large numbers) while pretending that their views aren’t internally contradictory, when, indeed, they are.

White liberals, full of sympathy toward blacks' ineptitude in creating their own falsehoods, are often willing to lend them a hand by offering them, and by telling on their behalf, a wonderfully well-crafted set of monumental lies sure to win the hearts of dishonest media pundits and corrupt judges.

Of course, some blacks might consider this unasked-for aid to be patronizing, and I can certainly understand their point of view. But liberals are liberals, and treating their inferiors with hypocritical condescension while at the same time assuring them, falsely, that they are “just as good as anybody else” is what liberals do.
Jenab6

The truth about Democrat election fraud in the 2020 election should not be compromised

Compromises aren't always good things. When you compromise the truth with a lie, what you get is a lie. Often the truth of a dispute isn't "somewhere in the middle," but, rather, one side is in the right and the other side is in the wrong and is lying and gaslighting with every breath they take.

Such is the case with the 2020 election. There was fraud. When the Left said that there was no evidence of fraud, they were lying. When that lie became untenable because the public generally became aware of the evidence of election fraud, the media switched lies and began saying, sure, there was a little fraud, just as happens with most elections, but it wasn't enough to change the election results.

That's the lie that the Left is on now.

The fraud was widespread, involving at least five states.

The fraud involved elected state officials, who called a halt to the vote counting to give the Democrat cheaters time to discover how many votes for Biden that they would need to fabricate, and/or how many votes for Trump to throw away.

The fraud consists of more than one million illegal ballots for Biden and many thousands of Trump votes that were intentionally lost.

We, the people, re-elected Donald Trump. They, the cheaters, most of whom are Democrats, are imposing Joe Biden upon us.

We want Trump because he is a leader who had kept many of his promises (some incompletely, some of which need more time).

We don't want Biden because he is a criminal who should be in prison for the treason of selling us out to the Chinese Communist Party.
Jenab6

A comment on race differences, censored by YouTube. Therefore posted here and many other places.

The politically correct style of identity politics is a leftist reaction to the fact that races are generally different in their abilities. Whenever the same initial conditions do not produce identical results for all of the races, the leftists insist that the cause is racism by those who end up with the better results, against those who end up with the poorer results.

You might have seen a TV commercial in which a white man and a black man are given equally long pieces of rope to climb up a hill. The rope is long enough to reach the hands of the white man. But the black man is in a hole, so the rope is not long enough to reach his hands. What the commercial does not make clear is why the black man was in that hole. I think that the viewer is supposed to assume that the hole was dug by the white man, who then pushed the black man into it. But, really, this isn't why blacks are disadvantaged so that equal opportunity does not lead to equal outcome. Instead, the problem is that the black man is inferior to the white man in certain ways that matter, quite a lot, in highly technological societies. The black man was _born_ in that metaphorical hole. The white man had nothing to do with his being there.

Some races are more suited than others for jobs that pertain to spaceflight. Some races are smarter than others. Some races are more conscientious than others. And so on. For any quality than you can name, there were be some racial variability in that quality. Race isn't simply skin color. Race is who your ancestors were, and the inherited characteristics and abilities that they transmitted to their descendants through biology.

While it is true that someone’s race doesn’t determine his individual IQ, it does determine the probability for a randomly chosen member of a race having an average IQ being at, or above, a specified value.

The normal distribution that most closely matches the IQ distribution of white male US citizens is 103.08±14.54 (Jensen & Reynolds, "Sex Differences on the WISC-R," _Personality & Individual Differences,_ volume 4, number 2, pp. 223-226, 1983).

The normal distribution that most closely matches the IQ distribution of US-resident mulattoes (usually called "blacks" or "African-Americans") is 85.0±13.0 (a typical finding of studies since 1950).

A good approximation of the fraction, f, of a race having an average IQ of x̄ and a standard deviation in IQ of σ, which is above the minimum IQ of μ, can be found as follows:

f(μ) = [σ√(2π)]⁻¹ ∫(μ,∞) exp{ −[(x−x̄)/σ]²/2 } dx

Taking advantage of the normal distribution's symmetry, we make it more easily integrable.

f(μ) = ½ − [σ√(2π)]⁻¹ ∫(x̄,μ) exp{ −[(x−x̄)/σ]²/2 } dx

You can avoid integrating the probability density function if you have a handy error function to call.

f(μ) = 1 − ½ { 1 + erf [(μ−x̄)/(σ√2)] }

Let us suppose that an employer wants to hire workers for a job that, in his opinion, requires a minimum IQ of 130 for satisfactory performance. He lives in an area that is demographically typical for the United States, where whites outnumber blacks by a ratio of five.

The fraction of whites who are qualified for the job on the basis of IQ is

f( μ=130.0, x̄=103.08, σ=14.54 ) = 0.0320528311

The fraction of blacks who are qualified for the job on the basis of IQ is

f( μ=130.0, x̄=85, σ=13 ) = 0.0002685491

If the population of whites and of blacks were equal in size, then the ratio of mentally qualified whites to mentally qualified blacks would be 119.355755.

Since whites outnumber blacks in the area where the employer's business is, by a ratio of five, the actual ratio of mentally qualified whites to mentally qualified blacks is 596.778775.

If the employer needs fewer than 100 new employees, it could very easily turn out that he will hire no blacks at all, _even if he uses no racism whatsoever in selecting his hirelings._ In fact, of the occasions in which this scenario plays out, and exactly 100 new workers are hired, the employer will have hired...

100 whites and 0 blacks on 84.5% of occasions
99 whites and 1 black on 14.2% of occasions
98 whites and 2 blacks on 1.2% of occasions
97− whites and 3+ blacks on 0.1% of occasions

Because the United States is a First World country in which most of the best jobs are mentally challenging jobs, purely free-market hiring practices will exclude a demographically disproportionately high fraction of low-average-IQ races from those jobs. This is normal and natural. It is the only way by which a country can remain competitive internationally, especially with countries that don't engage in politically correct tampering with the free market for labor. A focus on merit is a good thing. It is in conflict with diversity and inclusion. Therefore, diversity and inclusion are bad ideas, and to focus on them, instead of on merit, is harmful.